Fix the gmcs detection in configure.ac that was incorrectly causing

ThePimp to be built when gmcs wasn't there.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@2957 92316355-f0b4-4df1-b90c-862c8a59935f

configure.ac

@@ -171,7 +171,7 @@ fi
 
 # Build pipi-sharp?
 AC_PATH_PROG(GMCS, gmcs, no)
-AM_CONDITIONAL(USE_CSHARP, test "${gmcs}" != "no")
+AM_CONDITIONAL(USE_CSHARP, test "${GMCS}" != "no")
 
 # Build The Pimp?
 ac_cv_my_have_gtksharp=yes