[gimp] Makefile: libgimpui also introspected.

[Jehan <jehanp src gnome org>]

commit f74320d4dc5e92351001cd44c4380c95725eccd5
Author: Jehan <jehan girinstud io>
Date:   Mon Jul 29 02:08:27 2019 +0200

    Makefile: libgimpui also introspected.

 Makefile.am | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/Makefile.am b/Makefile.am
index ae51c9fcd1..39bfe4c4a3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -237,6 +237,7 @@ Gimp_@GIMP_API_MAJOR_VERSION@_@GIMP_API_MINOR_VERSION@_gir_LIBS = \
 
 Gimp_@GIMP_API_MAJOR_VERSION@_@GIMP_API_MINOR_VERSION@_gir_FILES =     \
        $(libgimp_introspectable)                                       \
+       $(libgimpui_introspectable)                                     \
        $(libgimpbase_introspectable)                                   \
        $(libgimpcolor_introspectable)                                  \
        $(libgimpconfig_introspectable)                                 \