Define _GNU_SOURCE.

diff --git a/libasprintf/autosprintf.cc b/libasprintf/autosprintf.cc
index b7b064b42724a3adb61c0510839df3a4f6d6b451..c145d5f333d7aa4a42935eb4a9f4564cf71788a7 100644 (file)
--- a/libasprintf/autosprintf.cc
+++ b/libasprintf/autosprintf.cc
@@ -17,6 +17,13 @@
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    USA.  */
 
+/* Tell glibc's <stdio.h> to provide a prototype for vasprintf().
+   This must come before <config.h> because <config.h> may include
+   <features.h>, and once <features.h> has been included, it's too late.  */
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE    1
+#endif
+
 /* Specification.  */
 #include "autosprintf.h"