From b31d0719fbd9362564d560f2ea776b50392e41d0 Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Thu, 12 Feb 2009 12:53:34 +0000
Subject: [PATCH] Don't call SetEnvironmentVariable() when removing an
 environment variable, as this seems to crash on at least some versions of
 MingW. Our current usage of this function does not require it, so it should
 be ok to ignore.

---
 src/port/win32env.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/port/win32env.c b/src/port/win32env.c
index 7533549608..36888286b7 100644
--- a/src/port/win32env.c
+++ b/src/port/win32env.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/port/win32env.c,v 1.1 2009/01/21 10:30:02 mha Exp $
+ *	  $PostgreSQL: pgsql/src/port/win32env.c,v 1.2 2009/02/12 12:53:34 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -64,12 +64,18 @@ pgwin32_putenv(const char *envval)
 		return -1;
 	*cp = '\0';
 	cp++;
-	if (strlen(cp) == 0)
-		cp = NULL;
-	if (!SetEnvironmentVariable(envcpy, cp))
+	if (strlen(cp))
 	{
-		free(envcpy);
-		return -1;
+		/*
+		 * Only call SetEnvironmentVariable() when we are adding a variable,
+		 * not when removing it. Calling it on both crashes on at least certain
+		 * versions of MingW.
+		 */
+		if (!SetEnvironmentVariable(envcpy, cp))
+		{
+			free(envcpy);
+			return -1;
+		}
 	}
 	free(envcpy);