3 files changed, 6 insertions, 0 deletions
diff --git a/jim-aio.c b/jim-aio.c
index 93e0b41..0631e40 100644
--- a/jim-aio.c
+++ b/jim-aio.c
@@ -39,7 +39,9 @@
 
 #include "jimautoconf.h"
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
diff --git a/jim-exec.c b/jim-exec.c
index 19b5128..6690c75 100644
--- a/jim-exec.c
+++ b/jim-exec.c
@@ -20,7 +20,9 @@
  * express or implied warranty.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <string.h>
 #include <ctype.h>
 
diff --git a/jim.c b/jim.c
index 3c52f74..bf98eb9 100644
--- a/jim.c
+++ b/jim.c
@@ -41,7 +41,9 @@
  * official policies, either expressed or implied, of the Jim Tcl Project.
  **/
 #define JIM_OPTIMIZATION        /* comment to avoid optimizations and reduce size */
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE             /* Mostly just for environ */
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>