[gtk/ci-update: 1/2] Check for diff's availability

[Emmanuele Bassi <ebassi src gnome org>]

commit 48cc26246f0b6bbc6d58d82831129560bff412cc
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Nov 1 15:20:47 2019 +0000

    Check for diff's availability
    
    The tests suite calls `diff` in various places, which means we need to
    check if it's installed.

 testsuite/meson.build | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/testsuite/meson.build b/testsuite/meson.build
index 10dabd8152..bb7c8160f4 100644
--- a/testsuite/meson.build
+++ b/testsuite/meson.build
@@ -2,6 +2,10 @@ gtk_libexecdir = join_paths(gtk_prefix, get_option('libexecdir'))
 installed_test_bindir = join_paths(gtk_libexecdir, 'installed-tests', 'gtk-4.0')
 installed_test_datadir = join_paths(gtk_datadir, 'installed-tests', 'gtk-4.0')
 
+# We call diff in various tests, so we need to check it's available,
+# otherwise we're going to have failures down the line
+diff = find_program('diff', required: true)
+
 subdir('gdk')
 subdir('gsk')
 subdir('gtk')