diff --git a/src/backend/parser/Makefile b/src/backend/parser/Makefile
index 00e8e88e9c2..c8fba3bbb0c 100644
--- a/src/backend/parser/Makefile
+++ b/src/backend/parser/Makefile
@@ -12,7 +12,7 @@ include $(top_builddir)/src/Makefile.global
 
 override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS)
 
-OBJS= analyze.o gram.o keywords.o kwlookup.o parser.o \
+OBJS= analyze.o gram.o scan.o keywords.o kwlookup.o parser.o \
       parse_agg.o parse_clause.o parse_coerce.o parse_collate.o parse_cte.o \
       parse_expr.o parse_func.o parse_node.o parse_oper.o parse_param.o \
       parse_relation.o parse_target.o parse_type.o parse_utilcmd.o scansup.o
@@ -22,12 +22,9 @@ FLEXFLAGS = -CF -b -p -p
 include $(top_srcdir)/src/backend/common.mk
 
 
-# scan is compiled as part of gram
-gram.o: scan.c
-
 # Latest flex causes warnings in this file.
 ifeq ($(GCC),yes)
-gram.o: CFLAGS += -Wno-error
+scan.o: CFLAGS += -Wno-error
 endif
 
 
@@ -58,7 +55,7 @@ endif
 
 
 # Force these dependencies to be known even without dependency info built:
-gram.o keywords.o parser.o: gram.h
+gram.o scan.o keywords.o parser.o: gram.h
 
 
 # gram.c, gram.h, and scan.c are in the distribution tarball, so they
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1d4d942f024..1a08ea47fdd 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -13374,13 +13374,3 @@ parser_init(base_yy_extra_type *yyext)
 {
 	yyext->parsetree = NIL;		/* in case grammar forgets to set it */
 }
-
-/*
- * Must undefine this stuff before including scan.c, since it has different
- * definitions for these macros.
- */
-#undef yyerror
-#undef yylval
-#undef yylloc
-
-#include "scan.c"
diff --git a/src/backend/parser/scan.l b/src/backend/parser/scan.l
index cde8fae620f..2a2895bac0d 100644
--- a/src/backend/parser/scan.l
+++ b/src/backend/parser/scan.l
@@ -1,4 +1,4 @@
-%{
+%top{
 /*-------------------------------------------------------------------------
  *
  * scan.l
@@ -6,7 +6,7 @@
  *
  * NOTE NOTE NOTE:
  *
- * The rules in this file must be kept in sync with psql's lexer!!!
+ * The rules in this file must be kept in sync with psql's psqlscan.l!
  *
  * The rules are designed so that the scanner never has to backtrack,
  * in the sense that there is always a rule that can match the input
@@ -34,12 +34,13 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "parser/gramparse.h"
 #include "parser/parser.h"				/* only needed for GUC variables */
-#include "parser/scanner.h"
 #include "parser/scansup.h"
 #include "mb/pg_wchar.h"
+}
 
-
+%{
 /* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */
 #undef fprintf
 #define fprintf(file, fmt, msg)  ereport(ERROR, (errmsg_internal("%s", msg)))
diff --git a/src/interfaces/ecpg/preproc/Makefile b/src/interfaces/ecpg/preproc/Makefile
index dd1e070625d..df83e29fc46 100644
--- a/src/interfaces/ecpg/preproc/Makefile
+++ b/src/interfaces/ecpg/preproc/Makefile
@@ -26,7 +26,7 @@ override CPPFLAGS := -I../include -I$(top_srcdir)/src/interfaces/ecpg/include \
 
 override CFLAGS += $(PTHREAD_CFLAGS) -DECPG_COMPILE
 
-OBJS=	preproc.o type.o ecpg.o output.o parser.o \
+OBJS=	preproc.o pgc.o type.o ecpg.o output.o parser.o \
 	keywords.o c_keywords.o ecpg_keywords.o kwlookup.o ../ecpglib/typename.o descriptor.o variable.o \
 	$(WIN32RES)
 
@@ -38,9 +38,6 @@ ecpg: $(OBJS) | submake-libpgport
 ../ecpglib/typename.o: ../ecpglib/typename.c
 	$(MAKE) -C $(dir $@) $(notdir $@)
 
-# pgc is compiled as part of preproc
-preproc.o: pgc.c
-
 preproc.h: preproc.c ;
 
 preproc.c: preproc.y
@@ -61,7 +58,7 @@ preproc.y: ../../../backend/parser/gram.y parse.pl ecpg.addons ecpg.header ecpg.
 	$(PERL) $(srcdir)/parse.pl $(srcdir) < $< > $@
 	$(PERL) $(srcdir)/check_rules.pl $(srcdir) $<
 
-ecpg_keywords.o c_keywords.o keywords.o preproc.o parser.o: preproc.h
+ecpg_keywords.o c_keywords.o keywords.o preproc.o pgc.o parser.o: preproc.h
 
 kwlookup.c: % : $(top_srcdir)/src/backend/parser/%
 	rm -f $@ && $(LN_S) $< .
diff --git a/src/interfaces/ecpg/preproc/ecpg.trailer b/src/interfaces/ecpg/preproc/ecpg.trailer
index 422013c934d..8ed2eb48612 100644
--- a/src/interfaces/ecpg/preproc/ecpg.trailer
+++ b/src/interfaces/ecpg/preproc/ecpg.trailer
@@ -1912,11 +1912,3 @@ void parser_init(void)
 {
  /* This function is empty. It only exists for compatibility with the backend parser right now. */
 }
-
-/*
- * Must undefine base_yylex before including pgc.c, since we want it
- * to create the function base_yylex not filtered_base_yylex.
- */
-#undef base_yylex
-
-#include "pgc.c"
diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index ef0fed7ab68..c8455b88d8b 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -1,4 +1,4 @@
-%{
+%top{
 /*-------------------------------------------------------------------------
  *
  * pgc.l
@@ -23,7 +23,19 @@
 #include <limits.h>
 
 #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;
 
 static int		xcdepth = 0;	/* depth of nesting in slash-star comments */