[PATCH:xmodmap] Add AC_USE_SYSTEM_EXTENSIONS to expose asprintf() in GNU libc headers

[Alan Coopersmith]

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=48696

Reported-by: Dominique Leuenberger
Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
---
 configure.ac |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/configure.ac b/configure.ac
index 952a900..3f04cca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,6 +29,8 @@ AC_INIT([xmodmap],
 	[xmodmap])
 AC_CONFIG_SRCDIR([Makefile.am])
 AC_CONFIG_HEADERS([config.h])
+# Needed for asprintf on GNU libc
+AC_USE_SYSTEM_EXTENSIONS
 
 # Initialize Automake
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
-- 
1.7.9.2