[gimp] Allow building GIMP of without vala.

[Jehan <jehanp src gnome org>]

commit 56982e6ce96d34b0802f90b5dd0606565f6b3914
Author: Kevin Cozens <kevin ve3syb ca>
Date:   Sat Jul 11 22:01:59 2020 -0400

    Allow building GIMP of without vala.
    
    To build GIMP without vala the arguments "--enable-vala=no --with-vala=no"
    must be used during the configuration process. If the --with-vala is not
    provided the build process will still try to build some vala based plug-ins.
    
    Fixes https://gitlab.gnome.org/GNOME/gimp/-/issues/5389

 configure.ac | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/configure.ac b/configure.ac
index 0d2ce0f58b..342743a32e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2440,6 +2440,7 @@ if test "x$with_vala" = xno; then
   warning_vala="
 WARNING: you disabled the installation of core Vala plug-ins. This
          is discouraged as it won't provide the full GIMP experience."
+  AM_CONDITIONAL(ENABLE_VAPIGEN, test "x$enable_vala" = "xyes")
 else
   VAPIGEN_CHECK($VALA_REQUIRED_VERSION)
   with_vala="yes"