[gimp/meson] Gtk+2 fails to build with strict-prototypes. Do not use Werror=.

[Félix Piédallu <fpiedallu src gnome org>]

commit f508df5172fdc126938dc880089dfc7aedcc5e27
Author: Félix Piédallu <felix piedallu me>
Date:   Fri Feb 16 17:13:36 2018 +0100

    Gtk+2 fails to build with strict-prototypes. Do not use Werror=.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 5d64727..8cf7596 100644
--- a/meson.build
+++ b/meson.build
@@ -922,9 +922,9 @@ warning_cflags = [
 
   # You can uncomment this to debug with less warning outputs
   # '-Wno-deprecated-declarations',
+  '-Wno-strict-prototypes',
 
   '-Werror=implicit-function-declaration',
-  '-Werror=strict-prototypes',
 ]
 add_project_arguments(cc .get_supported_arguments(warning_cflags), language: 'c')
 add_project_arguments(cxx.get_supported_arguments(warning_cflags), language: 'cpp')