[gimp] libgimp: (meson) set GIMP_DISABLE_DEPRECATED for introspection.

[Jehan <jehanp src gnome org>]

commit 5fe20497c52827086498b4c3bc6872e642ed3437
Author: Jehan <jehan girinstud io>
Date:   Sun Oct 20 16:47:40 2019 +0200

    libgimp: (meson) set GIMP_DISABLE_DEPRECATED for introspection.
    
    No need to introspect deprecated API, especially for the new non-C APIs
    after a major version update.
    This also sync both the autotools and meson-generated GIR files.
    See also #4018.

 libgimp/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/libgimp/meson.build b/libgimp/meson.build
index b3e3028538..7797b09771 100644
--- a/libgimp/meson.build
+++ b/libgimp/meson.build
@@ -385,6 +385,7 @@ else
       '-DGIMP_MODULE_COMPILATION',
       '-DGIMP_THUMB_COMPILATION',
       '-DGIMP_WIDGETS_COMPILATION',
+      '-DGIMP_DISABLE_DEPRECATED',
     ],
 
     includes: [