Add port support for unsetenv() in back branches. Needed for locale

environment fix.

configure

@@ -10531,7 +10531,8 @@ fi
 
 
 
-for ac_func in fseeko gethostname getrusage inet_aton random srandom strcasecmp strdup strerror strtol strtoul
+
+for ac_func in fseeko gethostname getrusage inet_aton random srandom strcasecmp strdup strerror strtol strtoul unsetenv
 do
 as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
 echo "$as_me:$LINENO: checking for $ac_func" >&5
@@ -11168,7 +11169,8 @@ echo "${ECHO_T}$ac_cv_header_syslog_h" >&6
 
 fi
 if test $ac_cv_header_syslog_h = yes; then
-  cat >>confdefs.h <<\_ACEOF
+
+cat >>confdefs.h <<\_ACEOF
 #define HAVE_SYSLOG 1
 _ACEOF
 

configure.in

@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.217.2.19 2005/12/09 20:56:45 tgl Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.217.2.20 2006/01/05 00:51:52 tgl Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -840,7 +840,7 @@ else
   AC_CHECK_FUNCS([fpclass fp_class fp_class_d class], [break])
 fi
 
-AC_REPLACE_FUNCS([fseeko gethostname getrusage inet_aton random srandom strcasecmp strdup strerror strtol strtoul])
+AC_REPLACE_FUNCS([fseeko gethostname getrusage inet_aton random srandom strcasecmp strdup strerror strtol strtoul unsetenv])
 
 # BSD/OS & NetBSD use a custom fseeko/ftello built on fsetpos/fgetpos
 # We override the previous test that said fseeko/ftello didn't exist
@@ -895,7 +895,7 @@ AC_MSG_RESULT(yes)],
 
 AC_CHECK_FUNC(syslog, 
 	     [AC_CHECK_HEADER(syslog.h,
-	     [AC_DEFINE(HAVE_SYSLOG, 1, [])],
+	     [AC_DEFINE(HAVE_SYSLOG, 1, [Define to 1 if you have the syslog interface.])],
 	     [])])
 
 AC_CACHE_CHECK([for optreset], pgac_cv_var_int_optreset,

src/include/c.h

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: c.h,v 1.130.2.1 2005/07/18 15:54:30 tgl Exp $
+ * $Id: c.h,v 1.130.2.2 2006/01/05 00:51:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -669,4 +669,8 @@ extern int	vsnprintf(char *str, size_t count, const char *fmt, va_list args);
 #define memmove(d, s, c)		bcopy(s, d, c)
 #endif
 
+#ifndef HAVE_UNSETENV
+extern void unsetenv(const char *name);
+#endif
+
 #endif   /* C_H */

src/include/pg_config.h.in

@@ -8,7 +8,7 @@
  * or in pg_config.h afterwards.  Of course, if you edit pg_config.h, then your
  * changes will be overwritten the next time you run configure.
  *
- * $Id: pg_config.h.in,v 1.32.2.1 2002/11/08 05:23:09 tgl Exp $
+ * $Id: pg_config.h.in,v 1.32.2.2 2006/01/05 00:51:52 tgl Exp $
  */
 
 #ifndef PG_CONFIG_H
@@ -441,6 +441,9 @@
 /* Set to 1 if you have isinf() */
 #undef HAVE_ISINF
 
+/* Define to 1 if you have the `unsetenv' function. */
+#undef HAVE_UNSETENV
+
 /*
  *	These are all related to port/isinf.c 
  */

src/port/unsetenv.c

@@ -0,0 +1,56 @@
+/*-------------------------------------------------------------------------
+ *
+ * unsetenv.c
+ *	  unsetenv() emulation for machines without it
+ *
+ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/port/unsetenv.c,v 1.6.4.1 2006/01/05 00:51:52 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+
+void
+unsetenv(const char *name)
+{
+	char	   *envstr;
+
+	if (getenv(name) == NULL)
+		return;					/* no work */
+
+	/*
+	 * The technique embodied here works if libc follows the Single Unix Spec
+	 * and actually uses the storage passed to putenv() to hold the environ
+	 * entry.  When we clobber the entry in the second step we are ensuring
+	 * that we zap the actual environ member.  However, there are some libc
+	 * implementations (notably recent BSDs) that do not obey SUS but copy the
+	 * presented string.  This method fails on such platforms.	Hopefully all
+	 * such platforms have unsetenv() and thus won't be using this hack.
+	 *
+	 * Note that repeatedly setting and unsetting a var using this code will
+	 * leak memory.
+	 */
+
+	envstr = (char *) malloc(strlen(name) + 2);
+	if (!envstr)				/* not much we can do if no memory */
+		return;
+
+	/* Override the existing setting by forcibly defining the var */
+	sprintf(envstr, "%s=", name);
+	putenv(envstr);
+
+	/* Now we can clobber the variable definition this way: */
+	strcpy(envstr, "=");
+
+	/*
+	 * This last putenv cleans up if we have multiple zero-length names as a
+	 * result of unsetting multiple things.
+	 */
+	putenv(envstr);
+}