[gegl] Define XOPEN feature test macro for PATH_MAX

[Martin Nordholts <martinn src gnome org>]

commit 37afabb60111bd65fa1527330d757926621f69d0
Author: Danny Robson <danny blubinc net>
Date:   Sat May 15 01:50:59 2010 +0000

    Define XOPEN feature test macro for PATH_MAX
    
    Does not appear to be an issue under gcc, though trips up at least
    clang. Still needs a more general fix as PATH_MAX is not strictly part
    of POSIX anyway..

 gegl/gegl-xml.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gegl/gegl-xml.c b/gegl/gegl-xml.c
index ec4fce2..7c71d07 100644
--- a/gegl/gegl-xml.c
+++ b/gegl/gegl-xml.c
@@ -17,6 +17,9 @@
  */
 #include "config.h"
 
+/* For clang, remove when getting rid of using PATH_MAX */
+#define _XOPEN_SOURCE 500
+
 #include <glib.h>
 #include <glib-object.h>
 #include <stdlib.h>