[PATCH:libICE] Add AC_USE_SYSTEM_EXTENSIONS to make asprintf() visible in GNU libc

[Alan Coopersmith]

asprintf is considered a GNU extension and thus one needs to define
_GNU_SOURCE before including stdio.h.

Reported-by: Cyril Brulebois <kibi at debian.org>
Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
---
 configure.ac |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/configure.ac b/configure.ac
index 03432f5..88fbcd7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -12,6 +12,11 @@ AC_CONFIG_HEADERS([config.h])
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
 AM_MAINTAINER_MODE
 
+# Set common system defines for POSIX extensions, such as _GNU_SOURCE
+# Must be called before any macros that run the compiler (like
+# AC_PROG_LIBTOOL or XORG_DEFAULT_OPTIONS) to avoid autoconf errors.
+AC_USE_SYSTEM_EXTENSIONS
+
 # Require xorg-macros minimum of 1.10 for DocBook XML documentation
 m4_ifndef([XORG_MACROS_VERSION],
           [m4_fatal([must install xorg-macros 1.10 or later before running autoconf/autogen])])
-- 
1.7.3.2