[gupnp-av] Add vapigen m4 macro

[Jens Georg <jensgeorg src gnome org>]

commit f90e9ceadf1229f342f1c067917a730452e064bf
Author: Jens Georg <mail jensge org>
Date:   Mon Oct 8 14:07:02 2012 +0200

    Add vapigen m4 macro

 m4/vapigen.m4 |   41 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 41 insertions(+), 0 deletions(-)
---
diff --git a/m4/vapigen.m4 b/m4/vapigen.m4
new file mode 100644
index 0000000..d8c86f6
--- /dev/null
+++ b/m4/vapigen.m4
@@ -0,0 +1,41 @@
+
+dnl vala.m4
+dnl
+dnl Copyright 2010 Marc-Andre Lureau
+dnl Copyright 2011 Rodney Dawes <dobey pwns gmail com>
+dnl
+dnl This library is free software; you can redistribute it and/or
+dnl modify it under the terms of the GNU Lesser General Public
+dnl License as published by the Free Software Foundation; either
+dnl version 2.1 of the License, or (at your option) any later version.
+dnl
+dnl This library is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+dnl Lesser General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU Lesser General Public
+dnl License along with this library; if not, write to the Free Software
+dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+
+dnl dropped everything but VALA_PROG_VAPIGEN - Jens Georg <mail jensge org>
+
+# Check whether the Vala API Generator exists in `PATH'. If it is found,
+# the variable VAPIGEN is set. Optionally a minimum release number of the
+# generator can be requested.
+#
+# VALA_PROG_VAPIGEN([MINIMUM-VERSION])
+# ------------------------------------
+AC_DEFUN([VALA_PROG_VAPIGEN],
+[AC_PATH_PROG([VAPIGEN], [vapigen], [])
+  AS_IF([test -z "$VAPIGEN"],
+    [AC_MSG_WARN([No Vala API Generator found. You will not be able to generate .vapi files.])],
+    [AS_IF([test -n "$1"],
+        [AC_MSG_CHECKING([$VAPIGEN is at least version $1])
+         am__vapigen_version=`$VAPIGEN --version | sed 's/Vala API Generator  *//'`
+         AS_VERSION_COMPARE([$1], ["$am__vapigen_version"],
+           [AC_MSG_RESULT([yes])],
+           [AC_MSG_RESULT([yes])],
+           [AC_MSG_RESULT([no])
+            AC_MSG_ERROR([Vala API Generator $1 not found.])])])])
+])