diff --git a/src/interfaces/ecpg/preproc/descriptor.c b/src/interfaces/ecpg/preproc/descriptor.c
index 22ee6bf2049..2f3799fdf0c 100644
--- a/src/interfaces/ecpg/preproc/descriptor.c
+++ b/src/interfaces/ecpg/preproc/descriptor.c
@@ -58,7 +58,7 @@ ECPGnumeric_lvalue(char *name)
 		case ECPGt_unsigned_long:
 		case ECPGt_unsigned_long_long:
 		case ECPGt_const:
-			fputs(name, yyout);
+			fputs(name, base_yyout);
 			break;
 		default:
 			mmerror(PARSE_ERROR, ET_ERROR, "variable \"%s\" must have a numeric type", name);
@@ -152,7 +152,7 @@ output_get_descr_header(char *desc_name)
 {
 	struct assignment *results;
 
-	fprintf(yyout, "{ ECPGget_desc_header(__LINE__, %s, &(", desc_name);
+	fprintf(base_yyout, "{ ECPGget_desc_header(__LINE__, %s, &(", desc_name);
 	for (results = assignments; results != NULL; results = results->next)
 	{
 		if (results->value == ECPGd_count)
@@ -162,7 +162,7 @@ output_get_descr_header(char *desc_name)
 	}
 
 	drop_assignments();
-	fprintf(yyout, "));\n");
+	fprintf(base_yyout, "));\n");
 	whenever_action(3);
 }
 
@@ -171,7 +171,7 @@ output_get_descr(char *desc_name, char *index)
 {
 	struct assignment *results;
 
-	fprintf(yyout, "{ ECPGget_desc(__LINE__, %s, %s,", desc_name, index);
+	fprintf(base_yyout, "{ ECPGget_desc(__LINE__, %s, %s,", desc_name, index);
 	for (results = assignments; results != NULL; results = results->next)
 	{
 		const struct variable *v = find_variable(results->variable);
@@ -188,12 +188,13 @@ output_get_descr(char *desc_name, char *index)
 			default:
 				break;
 		}
-		fprintf(yyout, "%s,", get_dtype(results->value));
-		ECPGdump_a_type(yyout, v->name, v->type, v->brace_level, NULL, NULL, -1, NULL, NULL, str_zero, NULL, NULL);
+		fprintf(base_yyout, "%s,", get_dtype(results->value));
+		ECPGdump_a_type(base_yyout, v->name, v->type, v->brace_level,
+						NULL, NULL, -1, NULL, NULL, str_zero, NULL, NULL);
 		free(str_zero);
 	}
 	drop_assignments();
-	fputs("ECPGd_EODT);\n", yyout);
+	fputs("ECPGd_EODT);\n", base_yyout);
 
 	whenever_action(2 | 1);
 }
@@ -203,7 +204,7 @@ output_set_descr_header(char *desc_name)
 {
 	struct assignment *results;
 
-	fprintf(yyout, "{ ECPGset_desc_header(__LINE__, %s, (int)(", desc_name);
+	fprintf(base_yyout, "{ ECPGset_desc_header(__LINE__, %s, (int)(", desc_name);
 	for (results = assignments; results != NULL; results = results->next)
 	{
 		if (results->value == ECPGd_count)
@@ -213,7 +214,7 @@ output_set_descr_header(char *desc_name)
 	}
 
 	drop_assignments();
-	fprintf(yyout, "));\n");
+	fprintf(base_yyout, "));\n");
 	whenever_action(3);
 }
 
@@ -264,7 +265,7 @@ output_set_descr(char *desc_name, char *index)
 {
 	struct assignment *results;
 
-	fprintf(yyout, "{ ECPGset_desc(__LINE__, %s, %s,", desc_name, index);
+	fprintf(base_yyout, "{ ECPGset_desc(__LINE__, %s, %s,", desc_name, index);
 	for (results = assignments; results != NULL; results = results->next)
 	{
 		const struct variable *v = find_variable(results->variable);
@@ -295,9 +296,11 @@ output_set_descr(char *desc_name, char *index)
 			case ECPGd_length:
 			case ECPGd_type:
 				{
-					char *str_zero = mm_strdup("0");
-					fprintf(yyout, "%s,", get_dtype(results->value));
-					ECPGdump_a_type(yyout, v->name, v->type, v->brace_level, NULL, NULL, -1, NULL, NULL, str_zero, NULL, NULL);
+					char	   *str_zero = mm_strdup("0");
+
+					fprintf(base_yyout, "%s,", get_dtype(results->value));
+					ECPGdump_a_type(base_yyout, v->name, v->type, v->brace_level,
+						   NULL, NULL, -1, NULL, NULL, str_zero, NULL, NULL);
 					free(str_zero);
 				}
 				break;
@@ -307,7 +310,7 @@ output_set_descr(char *desc_name, char *index)
 		}
 	}
 	drop_assignments();
-	fputs("ECPGd_EODT);\n", yyout);
+	fputs("ECPGd_EODT);\n", base_yyout);
 
 	whenever_action(2 | 1);
 }
diff --git a/src/interfaces/ecpg/preproc/ecpg.addons b/src/interfaces/ecpg/preproc/ecpg.addons
index 73a008c0db9..be1dcb77d47 100644
--- a/src/interfaces/ecpg/preproc/ecpg.addons
+++ b/src/interfaces/ecpg/preproc/ecpg.addons
@@ -8,7 +8,7 @@ ECPG: stmtClosePortalStmt block
 				if (connection)
 					mmerror(PARSE_ERROR, ET_ERROR, "AT option not allowed in CLOSE DATABASE statement");
 
-				fprintf(yyout, "{ ECPGdisconnect(__LINE__, \"CURRENT\");");
+				fprintf(base_yyout, "{ ECPGdisconnect(__LINE__, \"CURRENT\");");
 				whenever_action(2);
 				free($1);
 				break;
@@ -42,14 +42,14 @@ ECPG: stmtPrepareStmt block
 	}
 ECPG: stmtTransactionStmt block
 	{
-		fprintf(yyout, "{ ECPGtrans(__LINE__, %s, \"%s\");", connection ? connection : "NULL", $1);
+		fprintf(base_yyout, "{ ECPGtrans(__LINE__, %s, \"%s\");", connection ? connection : "NULL", $1);
 		whenever_action(2);
 		free($1);
 	}
 ECPG: stmtViewStmt rule
 	| ECPGAllocateDescr
 	{
-		fprintf(yyout,"ECPGallocate_desc(__LINE__, %s);",$1);
+		fprintf(base_yyout,"ECPGallocate_desc(__LINE__, %s);",$1);
 		whenever_action(0);
 		free($1);
 	}
@@ -58,7 +58,7 @@ ECPG: stmtViewStmt rule
 		if (connection)
 			mmerror(PARSE_ERROR, ET_ERROR, "AT option not allowed in CONNECT statement");
 
-		fprintf(yyout, "{ ECPGconnect(__LINE__, %d, %s, %d); ", compat, $1, autocommit);
+		fprintf(base_yyout, "{ ECPGconnect(__LINE__, %d, %s, %d); ", compat, $1, autocommit);
 		reset_variables();
 		whenever_action(2);
 		free($1);
@@ -69,7 +69,7 @@ ECPG: stmtViewStmt rule
 	}
 	| ECPGDeallocateDescr
 	{
-		fprintf(yyout,"ECPGdeallocate_desc(__LINE__, %s);",$1);
+		fprintf(base_yyout,"ECPGdeallocate_desc(__LINE__, %s);",$1);
 		whenever_action(0);
 		free($1);
 	}
@@ -79,10 +79,10 @@ ECPG: stmtViewStmt rule
 	}
 	| ECPGDescribe
 	{
-		fprintf(yyout, "{ ECPGdescribe(__LINE__, %d, %s,", compat, $1);
+		fprintf(base_yyout, "{ ECPGdescribe(__LINE__, %d, %s,", compat, $1);
 		dump_variables(argsresult, 1);
-		fputs("ECPGt_EORT);", yyout);
-		fprintf(yyout, "}");
+		fputs("ECPGt_EORT);", base_yyout);
+		fprintf(base_yyout, "}");
 		output_line_number();
 
 		free($1);
@@ -92,7 +92,7 @@ ECPG: stmtViewStmt rule
 		if (connection)
 			mmerror(PARSE_ERROR, ET_ERROR, "AT option not allowed in DISCONNECT statement");
 
-		fprintf(yyout, "{ ECPGdisconnect(__LINE__, %s);",
+		fprintf(base_yyout, "{ ECPGdisconnect(__LINE__, %s);",
 				$1 ? $1 : "\"CURRENT\"");
 		whenever_action(2);
 		free($1);
@@ -103,11 +103,11 @@ ECPG: stmtViewStmt rule
 		const char *con = connection ? connection : "NULL";
 
 		if (strcmp($1, "all") == 0)
-			fprintf(yyout, "{ ECPGdeallocate_all(__LINE__, %d, %s);", compat, con);
+			fprintf(base_yyout, "{ ECPGdeallocate_all(__LINE__, %d, %s);", compat, con);
 		else if ($1[0] == ':')
-			fprintf(yyout, "{ ECPGdeallocate(__LINE__, %d, %s, %s);", compat, con, $1+1);
+			fprintf(base_yyout, "{ ECPGdeallocate(__LINE__, %d, %s, %s);", compat, con, $1+1);
 		else
-			fprintf(yyout, "{ ECPGdeallocate(__LINE__, %d, %s, \"%s\");", compat, con, $1);
+			fprintf(base_yyout, "{ ECPGdeallocate(__LINE__, %d, %s, \"%s\");", compat, con, $1);
 
 		whenever_action(2);
 		free($1);
@@ -138,7 +138,7 @@ ECPG: stmtViewStmt rule
 	}
 	| ECPGSetAutocommit
 	{
-		fprintf(yyout, "{ ECPGsetcommit(__LINE__, \"%s\", %s);", $1, connection ? connection : "NULL");
+		fprintf(base_yyout, "{ ECPGsetcommit(__LINE__, \"%s\", %s);", $1, connection ? connection : "NULL");
 		whenever_action(2);
 		free($1);
 	}
@@ -147,7 +147,7 @@ ECPG: stmtViewStmt rule
 		if (connection)
 			mmerror(PARSE_ERROR, ET_ERROR, "AT option not allowed in SET CONNECTION statement");
 
-		fprintf(yyout, "{ ECPGsetconn(__LINE__, %s);", $1);
+		fprintf(base_yyout, "{ ECPGsetconn(__LINE__, %s);", $1);
 		whenever_action(2);
 		free($1);
 	}
@@ -169,7 +169,7 @@ ECPG: stmtViewStmt rule
 		if (connection)
 			mmerror(PARSE_ERROR, ET_ERROR, "AT option not allowed in TYPE statement");
 
-		fprintf(yyout, "%s", $1);
+		fprintf(base_yyout, "%s", $1);
 		free($1);
 		output_line_number();
 	}
diff --git a/src/interfaces/ecpg/preproc/ecpg.c b/src/interfaces/ecpg/preproc/ecpg.c
index 55ae30c534c..25e7d121bd3 100644
--- a/src/interfaces/ecpg/preproc/ecpg.c
+++ b/src/interfaces/ecpg/preproc/ecpg.c
@@ -162,11 +162,11 @@ main(int argc, char *const argv[])
 			case 'o':
 				output_filename = strdup(optarg);
 				if (strcmp(output_filename, "-") == 0)
-					yyout = stdout;
+					base_yyout = stdout;
 				else
-					yyout = fopen(output_filename, PG_BINARY_W);
+					base_yyout = fopen(output_filename, PG_BINARY_W);
 
-				if (yyout == NULL)
+				if (base_yyout == NULL)
 				{
 					fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 							progname, output_filename, strerror(errno));
@@ -229,7 +229,7 @@ main(int argc, char *const argv[])
 				break;
 			case 'd':
 #ifdef YYDEBUG
-				yydebug = 1;
+				base_yydebug = 1;
 #else
 				fprintf(stderr, _("%s: parser debug support (-d) not available\n"),
 						progname);
@@ -276,7 +276,7 @@ main(int argc, char *const argv[])
 			{
 				input_filename = mm_alloc(strlen("stdin") + 1);
 				strcpy(input_filename, "stdin");
-				yyin = stdin;
+				base_yyin = stdin;
 			}
 			else
 			{
@@ -300,13 +300,13 @@ main(int argc, char *const argv[])
 					ptr2ext[4] = '\0';
 				}
 
-				yyin = fopen(input_filename, PG_BINARY_R);
+				base_yyin = fopen(input_filename, PG_BINARY_R);
 			}
 
 			if (out_option == 0)	/* calculate the output name */
 			{
 				if (strcmp(input_filename, "stdin") == 0)
-					yyout = stdout;
+					base_yyout = stdout;
 				else
 				{
 					output_filename = strdup(input_filename);
@@ -316,8 +316,8 @@ main(int argc, char *const argv[])
 					ptr2ext[1] = (header_mode == true) ? 'h' : 'c';
 					ptr2ext[2] = '\0';
 
-					yyout = fopen(output_filename, PG_BINARY_W);
-					if (yyout == NULL)
+					base_yyout = fopen(output_filename, PG_BINARY_W);
+					if (base_yyout == NULL)
 					{
 						fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 								progname, output_filename, strerror(errno));
@@ -328,7 +328,7 @@ main(int argc, char *const argv[])
 				}
 			}
 
-			if (yyin == NULL)
+			if (base_yyin == NULL)
 				fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),
 						progname, argv[fnr], strerror(errno));
 			else
@@ -423,23 +423,23 @@ main(int argc, char *const argv[])
 				/* we need several includes */
 				/* but not if we are in header mode */
 				if (regression_mode)
-					fprintf(yyout, "/* Processed by ecpg (regression mode) */\n");
+					fprintf(base_yyout, "/* Processed by ecpg (regression mode) */\n");
 				else
-					fprintf(yyout, "/* Processed by ecpg (%d.%d.%d) */\n", MAJOR_VERSION, MINOR_VERSION, PATCHLEVEL);
+					fprintf(base_yyout, "/* Processed by ecpg (%d.%d.%d) */\n", MAJOR_VERSION, MINOR_VERSION, PATCHLEVEL);
 
 				if (header_mode == false)
 				{
-					fprintf(yyout, "/* These include files are added by the preprocessor */\n#include <ecpglib.h>\n#include <ecpgerrno.h>\n#include <sqlca.h>\n");
+					fprintf(base_yyout, "/* These include files are added by the preprocessor */\n#include <ecpglib.h>\n#include <ecpgerrno.h>\n#include <sqlca.h>\n");
 
 					/* add some compatibility headers */
 					if (INFORMIX_MODE)
-						fprintf(yyout, "/* Needed for informix compatibility */\n#include <ecpg_informix.h>\n");
+						fprintf(base_yyout, "/* Needed for informix compatibility */\n#include <ecpg_informix.h>\n");
 
-					fprintf(yyout, "/* End of automatic include section */\n");
+					fprintf(base_yyout, "/* End of automatic include section */\n");
 				}
 
 				if (regression_mode)
-					fprintf(yyout, "#define ECPGdebug(X,Y) ECPGdebug((X)+100,(Y))\n");
+					fprintf(base_yyout, "#define ECPGdebug(X,Y) ECPGdebug((X)+100,(Y))\n");
 
 				output_line_number();
 
@@ -454,10 +454,10 @@ main(int argc, char *const argv[])
 					if (!(ptr->opened))
 						mmerror(PARSE_ERROR, ET_WARNING, "cursor \"%s\" has been declared but not opened", ptr->name);
 
-				if (yyin != NULL && yyin != stdin)
-					fclose(yyin);
-				if (out_option == 0 && yyout != stdout)
-					fclose(yyout);
+				if (base_yyin != NULL && base_yyin != stdin)
+					fclose(base_yyin);
+				if (out_option == 0 && base_yyout != stdout)
+					fclose(base_yyout);
 
 				/*
 				 * If there was an error, delete the output file.
diff --git a/src/interfaces/ecpg/preproc/ecpg.header b/src/interfaces/ecpg/preproc/ecpg.header
index 75538e3bd96..6f08aeb3b73 100644
--- a/src/interfaces/ecpg/preproc/ecpg.header
+++ b/src/interfaces/ecpg/preproc/ecpg.header
@@ -72,7 +72,7 @@ mmerror(int error_code, enum errortype type, const char *error, ...)
 	/* internationalize the error message string */
 	error = _(error);
 
-	fprintf(stderr, "%s:%d: ", input_filename, yylineno);
+	fprintf(stderr, "%s:%d: ", input_filename, base_yylineno);
 
 	switch(type)
 	{
@@ -99,10 +99,10 @@ mmerror(int error_code, enum errortype type, const char *error, ...)
 			ret_value = error_code;
 			break;
 		case ET_FATAL:
-			if (yyin)
-				fclose(yyin);
-			if (yyout)
-				fclose(yyout);
+			if (base_yyin)
+				fclose(base_yyin);
+			if (base_yyout)
+				fclose(base_yyout);
 
 			if (strcmp(output_filename, "-") != 0 && unlink(output_filename) != 0)
 				fprintf(stderr, _("could not remove output file \"%s\"\n"), output_filename);
@@ -178,7 +178,7 @@ make3_str(char *str1, char *str2, char *str3)
 static char *
 make_name(void)
 {
-	return mm_strdup(yytext);
+	return mm_strdup(base_yytext);
 }
 
 static char *
diff --git a/src/interfaces/ecpg/preproc/ecpg.trailer b/src/interfaces/ecpg/preproc/ecpg.trailer
index 8ed2eb48612..42c2f3901e1 100644
--- a/src/interfaces/ecpg/preproc/ecpg.trailer
+++ b/src/interfaces/ecpg/preproc/ecpg.trailer
@@ -8,14 +8,14 @@ statement: ecpgstart at stmt ';' { connection = NULL; }
 				| ecpgstart stmt ';'
 				| ecpgstart ECPGVarDeclaration
 				{
-					fprintf(yyout, "%s", $2);
+					fprintf(base_yyout, "%s", $2);
 					free($2);
 					output_line_number();
 				}
 				| ECPGDeclaration
-				| c_thing               { fprintf(yyout, "%s", $1); free($1); }
-				| CPP_LINE              { fprintf(yyout, "%s", $1); free($1); }
-				| '{'                   { braces_open++; fputs("{", yyout); }
+				| c_thing               { fprintf(base_yyout, "%s", $1); free($1); }
+				| CPP_LINE              { fprintf(base_yyout, "%s", $1); free($1); }
+				| '{'                   { braces_open++; fputs("{", base_yyout); }
 				| '}'
 		{
 			remove_typedefs(braces_open);
@@ -25,7 +25,7 @@ statement: ecpgstart at stmt ';' { connection = NULL; }
 				free(current_function);
 				current_function = NULL;
 			}
-			fputs("}", yyout);
+			fputs("}", base_yyout);
 		}
 		;
 
@@ -380,10 +380,10 @@ ecpg_interval:	opt_interval	{ $$ = $1; }
  * variable declaration inside exec sql declare block
  */
 ECPGDeclaration: sql_startdeclare
-		{ fputs("/* exec sql begin declare section */", yyout); }
+		{ fputs("/* exec sql begin declare section */", base_yyout); }
 		var_type_declarations sql_enddeclare
 		{
-			fprintf(yyout, "%s/* exec sql end declare section */", $3);
+			fprintf(base_yyout, "%s/* exec sql end declare section */", $3);
 			free($3);
 			output_line_number();
 		}
@@ -417,7 +417,7 @@ type_declaration: S_TYPEDEF
 	{
 		add_typedef($5, $6.index1, $6.index2, $3.type_enum, $3.type_dimension, $3.type_index, initializer, *$4 ? 1 : 0);
 
-		fprintf(yyout, "typedef %s %s %s %s;\n", $3.type_str, *$4 ? "*" : "", $5, $6.str);
+		fprintf(base_yyout, "typedef %s %s %s %s;\n", $3.type_str, *$4 ? "*" : "", $5, $6.str);
 		output_line_number();
 		$$ = mm_strdup("");
 	};
@@ -1905,7 +1905,7 @@ void base_yyerror(const char *error)
 {
 	/* translator: %s is typically the translation of "syntax error" */
 	mmerror(PARSE_ERROR, ET_ERROR, "%s at or near \"%s\"",
-			_(error), token_start ? token_start : yytext);
+			_(error), token_start ? token_start : base_yytext);
 }
 
 void parser_init(void)
diff --git a/src/interfaces/ecpg/preproc/extern.h b/src/interfaces/ecpg/preproc/extern.h
index ccf5548f577..04af864aa1f 100644
--- a/src/interfaces/ecpg/preproc/extern.h
+++ b/src/interfaces/ecpg/preproc/extern.h
@@ -34,15 +34,15 @@ extern char *descriptor_index;
 extern char *descriptor_name;
 extern char *connection;
 extern char *input_filename;
-extern char *yytext,
+extern char *base_yytext,
 		   *token_start;
 
 #ifdef YYDEBUG
-extern int	yydebug;
+extern int	base_yydebug;
 #endif
-extern int	yylineno;
-extern FILE *yyin,
-		   *yyout;
+extern int	base_yylineno;
+extern FILE *base_yyin,
+		   *base_yyout;
 extern char *output_filename;
 
 extern struct _include_path *include_paths;
diff --git a/src/interfaces/ecpg/preproc/output.c b/src/interfaces/ecpg/preproc/output.c
index 007c07c0342..fffcda7cde9 100644
--- a/src/interfaces/ecpg/preproc/output.c
+++ b/src/interfaces/ecpg/preproc/output.c
@@ -11,7 +11,7 @@ output_line_number(void)
 {
 	char	   *line = hashline_number();
 
-	fprintf(yyout, "%s", line);
+	fprintf(base_yyout, "%s", line);
 	free(line);
 }
 
@@ -37,22 +37,22 @@ print_action(struct when * w)
 	switch (w->code)
 	{
 		case W_SQLPRINT:
-			fprintf(yyout, "sqlprint();");
+			fprintf(base_yyout, "sqlprint();");
 			break;
 		case W_GOTO:
-			fprintf(yyout, "goto %s;", w->command);
+			fprintf(base_yyout, "goto %s;", w->command);
 			break;
 		case W_DO:
-			fprintf(yyout, "%s;", w->command);
+			fprintf(base_yyout, "%s;", w->command);
 			break;
 		case W_STOP:
-			fprintf(yyout, "exit (1);");
+			fprintf(base_yyout, "exit (1);");
 			break;
 		case W_BREAK:
-			fprintf(yyout, "break;");
+			fprintf(base_yyout, "break;");
 			break;
 		default:
-			fprintf(yyout, "{/* %d not implemented yet */}", w->code);
+			fprintf(base_yyout, "{/* %d not implemented yet */}", w->code);
 			break;
 	}
 }
@@ -63,24 +63,24 @@ whenever_action(int mode)
 	if ((mode & 1) == 1 && when_nf.code != W_NOTHING)
 	{
 		output_line_number();
-		fprintf(yyout, "\nif (sqlca.sqlcode == ECPG_NOT_FOUND) ");
+		fprintf(base_yyout, "\nif (sqlca.sqlcode == ECPG_NOT_FOUND) ");
 		print_action(&when_nf);
 	}
 	if (when_warn.code != W_NOTHING)
 	{
 		output_line_number();
-		fprintf(yyout, "\nif (sqlca.sqlwarn[0] == 'W') ");
+		fprintf(base_yyout, "\nif (sqlca.sqlwarn[0] == 'W') ");
 		print_action(&when_warn);
 	}
 	if (when_error.code != W_NOTHING)
 	{
 		output_line_number();
-		fprintf(yyout, "\nif (sqlca.sqlcode < 0) ");
+		fprintf(base_yyout, "\nif (sqlca.sqlcode < 0) ");
 		print_action(&when_error);
 	}
 
 	if ((mode & 2) == 2)
-		fputc('}', yyout);
+		fputc('}', base_yyout);
 
 	output_line_number();
 }
@@ -91,7 +91,7 @@ hashline_number(void)
 	/* do not print line numbers if we are in debug mode */
 	if (input_filename
 #ifdef YYDEBUG
-		&& !yydebug
+		&& !base_yydebug
 #endif
 		)
 	{
@@ -100,7 +100,7 @@ hashline_number(void)
 		char	   *src,
 				   *dest;
 
-		sprintf(line, "\n#line %d \"", yylineno);
+		sprintf(line, "\n#line %d \"", base_yylineno);
 		src = input_filename;
 		dest = line + strlen(line);
 		while (*src)
@@ -128,27 +128,27 @@ static char *ecpg_statement_type_name[] = {
 void
 output_statement(char *stmt, int whenever_mode, enum ECPG_statement_type st)
 {
-	fprintf(yyout, "{ ECPGdo(__LINE__, %d, %d, %s, %d, ", compat, force_indicator, connection ? connection : "NULL", questionmarks);
+	fprintf(base_yyout, "{ ECPGdo(__LINE__, %d, %d, %s, %d, ", compat, force_indicator, connection ? connection : "NULL", questionmarks);
 	if (st == ECPGst_execute || st == ECPGst_exec_immediate)
 	{
-		fprintf(yyout, "%s, %s, ", ecpg_statement_type_name[st], stmt);
+		fprintf(base_yyout, "%s, %s, ", ecpg_statement_type_name[st], stmt);
 	}
 	else
 	{
 		if (st == ECPGst_prepnormal && auto_prepare)
-			fputs("ECPGst_prepnormal, \"", yyout);
+			fputs("ECPGst_prepnormal, \"", base_yyout);
 		else
-			fputs("ECPGst_normal, \"", yyout);
+			fputs("ECPGst_normal, \"", base_yyout);
 
 		output_escaped_str(stmt, false);
-		fputs("\", ", yyout);
+		fputs("\", ", base_yyout);
 	}
 
 	/* dump variables to C file */
 	dump_variables(argsinsert, 1);
-	fputs("ECPGt_EOIT, ", yyout);
+	fputs("ECPGt_EOIT, ", base_yyout);
 	dump_variables(argsresult, 1);
-	fputs("ECPGt_EORT);", yyout);
+	fputs("ECPGt_EORT);", base_yyout);
 	reset_variables();
 
 	whenever_action(whenever_mode | 2);
@@ -160,11 +160,11 @@ output_statement(char *stmt, int whenever_mode, enum ECPG_statement_type st)
 void
 output_prepare_statement(char *name, char *stmt)
 {
-	fprintf(yyout, "{ ECPGprepare(__LINE__, %s, %d, ", connection ? connection : "NULL", questionmarks);
+	fprintf(base_yyout, "{ ECPGprepare(__LINE__, %s, %d, ", connection ? connection : "NULL", questionmarks);
 	output_escaped_str(name, true);
-	fputs(", ", yyout);
+	fputs(", ", base_yyout);
 	output_escaped_str(stmt, true);
-	fputs(");", yyout);
+	fputs(");", base_yyout);
 	whenever_action(2);
 	free(name);
 	if (connection != NULL)
@@ -178,12 +178,12 @@ output_deallocate_prepare_statement(char *name)
 
 	if (strcmp(name, "all") != 0)
 	{
-		fprintf(yyout, "{ ECPGdeallocate(__LINE__, %d, %s, ", compat, con);
+		fprintf(base_yyout, "{ ECPGdeallocate(__LINE__, %d, %s, ", compat, con);
 		output_escaped_str(name, true);
-		fputs(");", yyout);
+		fputs(");", base_yyout);
 	}
 	else
-		fprintf(yyout, "{ ECPGdeallocate_all(__LINE__, %d, %s);", compat, con);
+		fprintf(base_yyout, "{ ECPGdeallocate_all(__LINE__, %d, %s);", compat, con);
 
 	whenever_action(2);
 	free(name);
@@ -203,16 +203,16 @@ output_escaped_str(char *str, bool quoted)
 	{
 		i = 1;
 		len--;
-		fputs("\"", yyout);
+		fputs("\"", base_yyout);
 	}
 
 	/* output this char by char as we have to filter " and \n */
 	for (; i < len; i++)
 	{
 		if (str[i] == '"')
-			fputs("\\\"", yyout);
+			fputs("\\\"", base_yyout);
 		else if (str[i] == '\n')
-			fputs("\\\n", yyout);
+			fputs("\\\n", base_yyout);
 		else if (str[i] == '\\')
 		{
 			int			j = i;
@@ -230,17 +230,17 @@ output_escaped_str(char *str, bool quoted)
 
 			if ((str[j] != '\n') && (str[j] != '\r' || str[j + 1] != '\n'))		/* not followed by a
 																				 * newline */
-				fputs("\\\\", yyout);
+				fputs("\\\\", base_yyout);
 		}
 		else if (str[i] == '\r' && str[i + 1] == '\n')
 		{
-			fputs("\\\r\n", yyout);
+			fputs("\\\r\n", base_yyout);
 			i++;
 		}
 		else
-			fputc(str[i], yyout);
+			fputc(str[i], base_yyout);
 	}
 
 	if (quoted && str[0] == '\"' && str[len] == '\"')
-		fputs("\"", yyout);
+		fputs("\"", base_yyout);
 }
diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index d104f601efc..3aa63ae2c13 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -24,19 +24,10 @@
 
 #include "extern.h"
 #include "preproc.h"
-
-/*
- * Change symbol names as expected by preproc.y.  It'd be better to do this
- * with %option prefix="base_yy", but that affects some other names that
- * various files expect *not* to be prefixed with "base_".  Cleaning it up
- * is not worth the trouble right now.
- */
-#define yylex           base_yylex
-#define yylval          base_yylval
 }
 
 %{
-extern YYSTYPE yylval;
+extern YYSTYPE base_yylval;
 
 static int		xcdepth = 0;	/* depth of nesting in slash-star comments */
 static char	   *dolqstart = NULL;	/* current $foo$ quote start string */
@@ -97,6 +88,7 @@ static struct _if_value
 %option noinput
 %option noyywrap
 %option warn
+%option prefix="base_yy"
 
 %option yylineno
 
@@ -426,7 +418,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 					BEGIN(SQL);
 					if (literalbuf[strspn(literalbuf, "01") + 1] != '\0')
 						mmerror(PARSE_ERROR, ET_ERROR, "invalid bit string literal");
-					yylval.str = mm_strdup(literalbuf);
+					base_yylval.str = mm_strdup(literalbuf);
 					return BCONST;
 				}
 
@@ -446,7 +438,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 <xh>{quotefail}	{
 				yyless(1);
 				BEGIN(SQL);
-				yylval.str = mm_strdup(literalbuf);
+				base_yylval.str = mm_strdup(literalbuf);
 				return XCONST;
 			}
 
@@ -489,27 +481,27 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 <xq,xqc>{quotefail} {
 				yyless(1);
 				BEGIN(state_before);
-				yylval.str = mm_strdup(literalbuf);
+				base_yylval.str = mm_strdup(literalbuf);
 				return SCONST;
 			}
 <xe>{quotestop} |
 <xe>{quotefail} {
 				yyless(1);
 				BEGIN(state_before);
-				yylval.str = mm_strdup(literalbuf);
+				base_yylval.str = mm_strdup(literalbuf);
 				return ECONST;
 			}
 <xn>{quotestop} |
 <xn>{quotefail} {
 				yyless(1);
 				BEGIN(state_before);
-				yylval.str = mm_strdup(literalbuf);
+				base_yylval.str = mm_strdup(literalbuf);
 				return NCONST;
 			}
 <xus>{xusstop} {
 				addlit(yytext, yyleng);
 				BEGIN(state_before);
-				yylval.str = mm_strdup(literalbuf);
+				base_yylval.str = mm_strdup(literalbuf);
 				return UCONST;
 			}
 <xq,xe,xn,xus>{xqdouble}	{ addlitchar('\''); }
@@ -550,7 +542,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 					addlit(yytext, yyleng);
 					free(dolqstart);
 					BEGIN(SQL);
-					yylval.str = mm_strdup(literalbuf);
+					base_yylval.str = mm_strdup(literalbuf);
 					return DOLCONST;
 				}
 				else
@@ -587,12 +579,12 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 						if (literallen == 0)
 							mmerror(PARSE_ERROR, ET_ERROR, "zero-length delimited identifier");
 						/* The backend will truncate the identifier here. We do not as it does not change the result. */
-						yylval.str = mm_strdup(literalbuf);
+						base_yylval.str = mm_strdup(literalbuf);
 						return CSTRING;
 					}
 <xdc>{xdstop}		{
 						BEGIN(state_before);
-						yylval.str = mm_strdup(literalbuf);
+						base_yylval.str = mm_strdup(literalbuf);
 						return CSTRING;
 					}
 <xui>{xuistop}		{
@@ -601,7 +593,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 							mmerror(PARSE_ERROR, ET_ERROR, "zero-length delimited identifier");
 						/* The backend will truncate the identifier here. We do not as it does not change the result. */
 						addlit(yytext, yyleng);
-						yylval.str = mm_strdup(literalbuf);
+						base_yylval.str = mm_strdup(literalbuf);
 						return UIDENT;
 					}
 <xd,xui>{xddouble}		{ addlitchar('"'); }
@@ -697,13 +689,13 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 
 						/* Convert "!=" operator to "<>" for compatibility */
 						if (strcmp(yytext, "!=") == 0)
-							yylval.str = mm_strdup("<>");
+							base_yylval.str = mm_strdup("<>");
 						else
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 						return Op;
 					}
 <SQL>{param}		{
-						yylval.ival = atol(yytext+1);
+						base_yylval.ival = atol(yytext+1);
 						return PARAM;
 					}
 <C,SQL>{integer}	{
@@ -720,36 +712,36 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 							)
 						{
 							errno = 0;
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 							return FCONST;
 						}
-						yylval.ival = val;
+						base_yylval.ival = val;
 						return ICONST;
 					}
 <SQL>{ip}			{
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return IP;
 				}
 <C,SQL>{decimal}	{
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return FCONST;
 			}
 <C,SQL>{real}		{
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return FCONST;
 			}
 <SQL>{realfail1}	{
 						yyless(yyleng-1);
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return FCONST;
 					}
 <SQL>{realfail2}	{
 						yyless(yyleng-2);
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return FCONST;
 					}
 <SQL>:{identifier}((("->"|\.){identifier})|(\[{array}\]))*	{
-						yylval.str = mm_strdup(yytext+1);
+						base_yylval.str = mm_strdup(yytext+1);
 						return(CVARIABLE);
 					}
 <SQL>{identifier}	{
@@ -775,7 +767,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 							 * to do so; that's just another way that ecpg could get
 							 * out of step with the backend.
 							 */
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 							return IDENT;
 						}
 					}
@@ -796,11 +788,11 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 						char* endptr;
 
 						errno = 0;
-						yylval.ival = strtoul((char *)yytext,&endptr,16);
+						base_yylval.ival = strtoul((char *)yytext,&endptr,16);
 						if (*endptr != '\0' || errno == ERANGE)
 						{
 							errno = 0;
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 							return SCONST;
 						}
 						return ICONST;
@@ -813,7 +805,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 						}
 						else
 						{
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 							return(CPP_LINE);
 						}
 					}
@@ -825,12 +817,12 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 						}
 						else
 						{
-							yylval.str = mm_strdup(yytext);
+							base_yylval.str = mm_strdup(yytext);
 							return(CPP_LINE);
 						}
 					}
 <C,SQL>{cppline}	{
-						yylval.str = mm_strdup(yytext);
+						base_yylval.str = mm_strdup(yytext);
 						return(CPP_LINE);
 					}
 <C>{identifier}		{
@@ -855,7 +847,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 								return keyword->value;
 							else
 							{
-								yylval.str = mm_strdup(yytext);
+								base_yylval.str = mm_strdup(yytext);
 								return IDENT;
 							}
 						}
diff --git a/src/interfaces/ecpg/preproc/variable.c b/src/interfaces/ecpg/preproc/variable.c
index 1b181b9dd41..8e66e4122bf 100644
--- a/src/interfaces/ecpg/preproc/variable.c
+++ b/src/interfaces/ecpg/preproc/variable.c
@@ -452,7 +452,7 @@ dump_variables(struct arguments * list, int mode)
 	dump_variables(list->next, mode);
 
 	/* Then the current element and its indicator */
-	ECPGdump_a_type(yyout, list->variable->name, list->variable->type, list->variable->brace_level,
+	ECPGdump_a_type(base_yyout, list->variable->name, list->variable->type, list->variable->brace_level,
 					list->indicator->name, list->indicator->type, list->indicator->brace_level,
 					NULL, NULL, str_zero, NULL, NULL);