[gimp] INSTALL: add GObject Introspection dependencies.

[Jehan <jehanp src gnome org>]

commit 814ff02ab44fb94cd7775fff3a8aefd0c3e2f363
Author: Jehan <jehan girinstud io>
Date:   Mon Aug 5 20:58:07 2019 +0200

    INSTALL: add GObject Introspection dependencies.

 INSTALL.in | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index 109f03c1f7..2dd6453c46 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -117,9 +117,9 @@ header files installed.
      respectively decoding and encoding), otherwise the plug-in is
      mostly useless.
 
- 14. The Python extension requires Python 2 development headers (@PYTHON2_REQUIRED_VERSION@
-     or newer) to be present. You will also need PyGTK and the
-     respective development headers.
+ 14. GObject Introspection requires the following dependencies to be
+     built and installed with introspection as well: cairo, GdkPixbuf,
+     GEGL, GIO, GLib, GObject and GTK+.
 
  15. Windows builds can now generate backtrace logs upon a crash.
      The logs will be available in: %APPDATA%\GIMP\@GIMP_APP_VERSION@\CrashLog\