[libgda] Correctly run GraphViz test case to determine if it has the new API

[Vivien Malerba <vivien src gnome org>]

commit 6a712fe895f70110a55ef8a9708de7f2fda8494d
Author: Vivien Malerba <malerba gnome-db org>
Date:   Thu Dec 19 22:02:56 2013 +0100

    Correctly run GraphViz test case to determine if it has the new API
    
    
    Thanks to Ulrich Weigand <uweigand de ibm com>

 configure.ac |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 56d79b2..cd86cb9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -261,6 +261,8 @@ then
                then
                        dnl test if new API is supported
                        AC_MSG_CHECKING([whether Graphviz's new API is supported])
+                       graphviz_save_CFLAGS=$CFLAGS
+                       CFLAGS="$CFLAGS $GRAPHVIZ_CFLAGS"
                        AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 #include <gvc.h>
 int main() {
@@ -270,6 +272,7 @@ int main() {
 }
 ])],
                         graphviz_new_api=yes, graphviz_new_api=no)
+                       CLFAGS=$graphviz_save_CFLAGS
 
                        AC_MSG_RESULT($graphviz_new_api)
                        if test "$graphviz_new_api" = "yes"; then