merges r29378 from trunk into ruby_1_9_2.

--
* win32/win32.c (rb_w32_getenv): should return NULL if specified name
  is empty. a patch from Heesob Park at [ruby-core:32650]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30025 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 2 deletions

diff --git a/win32/win32.c b/win32/win32.c
index c3bd4dcf55..94b67206b8 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -3876,8 +3876,8 @@ rb_w32_getenv(const char *name)
     int len = strlen(name);
     char *env;
 
-    if (envarea)
-	FreeEnvironmentStrings(envarea);
+    if (len == 0) return NULL;
+    if (envarea) FreeEnvironmentStrings(envarea);
     envarea = GetEnvironmentStrings();
     if (!envarea) {
 	map_errno(GetLastError());