[gimp] libgimp: fix introspection of PDB functions in meson build.

[Jehan <jehanp src gnome org>]

commit cf276ed972608c167abac56ff1d8252fc353e2eb
Author: Jehan <jehan girinstud io>
Date:   Sat Sep 14 23:24:35 2019 +0200

    libgimp: fix introspection of PDB functions in meson build.
    
    PDB headers had been forgotten and therefore a whole bunch of functions
    were not introspected.

 libgimp/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/libgimp/meson.build b/libgimp/meson.build
index e28c37e567..0d0cae4cc4 100644
--- a/libgimp/meson.build
+++ b/libgimp/meson.build
@@ -208,6 +208,7 @@ libgimp_headers_introspectable = [
   'gimpthumbnailprocedure.h',
   'gimptypes.h',
   'gimpvectors.h',
+  pdb_wrappers_headers,
 ]
 
 libgimp_headers = [