Pick up redefinition protection from tcpdump.

In case _DEFAULT_SOURCE or _BSD_SOURCE have already been defined, don't
redefine them, as that will get warnings that may turn into errors.

1 files changed, 11 insertions, 2 deletions

diff --git a/ftmacros.h b/ftmacros.h
index 3fafab80..3cd75056 100644
--- a/ftmacros.h
+++ b/ftmacros.h
@@ -105,9 +105,18 @@
    * don't whine about _BSD_SOURCE being deprecated; we still have
    * to define _BSD_SOURCE to handle older versions of GNU libc that
    * don't support _DEFAULT_SOURCE.
+   *
+   * But, if it's already defined, don't define it, so that we don't
+   * get a warning of it being redefined if it's defined as, for
+   * example, 1.
    */
-  #define _DEFAULT_SOURCE
-  #define _BSD_SOURCE
+  #ifndef _DEFAULT_SOURCE
+    #define _DEFAULT_SOURCE
+  #endif
+  /* Avoid redefining _BSD_SOURCE if it's already defined as for ex. 1 */
+  #ifndef _BSD_SOURCE
+    #define _BSD_SOURCE
+  #endif
 #endif
 
 #endif