Use gnustep-config if available

* configure.ac (--with-gnustep): Document this.
(NS_GNUSTEP_CONFIG): New variable, set if gnustep-config works.
If gnustep-config works, use 'gnustep-config --objc-flags' and
'gnustep-config --gui-libs' to compute GNUstep configuration
variables, instead of attempting to infer them individually.
* etc/NEWS: Document this.
* src/emacs.c [NS_IMPL_GNUSTEP]: Don't include <GNUstepBase/GSConfig.h>.
It doesn't appear to be needed, and the inclusion breaks on
Ubuntu 14.10 when 'configure' uses 'gnustep-config'.
Fixes: bug#19507

2 files changed, 8 insertions, 0 deletions

diff --git a/etc/ChangeLog b/etc/ChangeLog
index 47f61f4d7fd..55b835c0cf9 100644
--- a/etc/ChangeLog
+++ b/etc/ChangeLog
@@ -1,3 +1,8 @@
+2015-01-25  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Use gnustep-config if available
+        * NEWS: Document this.
+
 2015-01-22  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't downcase system diagnostics' first letters
diff --git a/etc/NEWS b/etc/NEWS
index db47033fb35..d5baed3dae7 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -36,6 +36,9 @@ should be able to work around the problem either by porting the Emacs
 undumping code to GCC under IRIX, or by configuring --with-wide-int,
 or by sticking with Emacs 24.4.
 
+** 'configure' now prefers gnustep-config when configuring GNUstep.
+If gnustep-config is not available, the old heuristics are used.
+
 ---
 ** The configure option `--with-pkg-config-prog' has been removed.
 Use './configure PKG_CONFIG=/full/name/of/pkg-config' if you need to.