diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index b4c61807b5..fa921e46cf 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,8 @@
+2013-03-17  Eli Zaretskii  <eliz@gnu.org>
+
+	* setenv.c [!HAVE_ENVIRON_DECL]: Avoid declaring environ if it is
+	a macro, as this causes compiler warnings with MinGW.
+
 2013-03-01  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* obstacks.texi (Obstacks): Trim @node to only contain the
diff --git a/libiberty/setenv.c b/libiberty/setenv.c
index 96917d5769..921e968860 100644
--- a/libiberty/setenv.c
+++ b/libiberty/setenv.c
@@ -63,8 +63,11 @@ extern int errno;
 
 #define __environ	environ
 #ifndef HAVE_ENVIRON_DECL
+/* MinGW defines environ to call a function.  */
+#ifndef environ
 extern char **environ;
 #endif
+#endif
 
 #undef setenv
 #undef unsetenv