diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index f0f9c66487c..6f37822c887 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -854,7 +854,9 @@ PostmasterMain(int argc, char *argv[])
 	/* For debugging: display postmaster environment */
 	if (message_level_is_interesting(DEBUG3))
 	{
+#if !defined(WIN32) || defined(_MSC_VER)
 		extern char **environ;
+#endif
 		char	  **p;
 		StringInfoData si;
 
diff --git a/src/backend/utils/misc/ps_status.c b/src/backend/utils/misc/ps_status.c
index 9da63774020..27798dc51e1 100644
--- a/src/backend/utils/misc/ps_status.c
+++ b/src/backend/utils/misc/ps_status.c
@@ -23,7 +23,9 @@
 #include "utils/guc.h"
 #include "utils/ps_status.h"
 
+#if !defined(WIN32) || defined(_MSC_VER)
 extern char **environ;
+#endif
 
 /* GUC variable */
 bool		update_process_title = DEFAULT_UPDATE_PROCESS_TITLE;
diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c
index 8309166f5b2..64460327f40 100644
--- a/src/test/regress/regress.c
+++ b/src/test/regress/regress.c
@@ -647,7 +647,9 @@ PG_FUNCTION_INFO_V1(get_environ);
 Datum
 get_environ(PG_FUNCTION_ARGS)
 {
+#if !defined(WIN32) || defined(_MSC_VER)
 	extern char **environ;
+#endif
 	int			nvals = 0;
 	ArrayType  *result;
 	Datum	   *env;