[gnome-builder] beautifier: Warn at build-time of missing beautifier programs

[Christian Hergert <chergert src gnome org>]

commit 8893fa07a44a34cf590587bfa7dd67c40f559fb2
Author: vanadiae <vanadiae35 gmail com>
Date:   Fri Mar 19 17:17:08 2021 +0100

    beautifier: Warn at build-time of missing beautifier programs

 src/plugins/beautifier/meson.build | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/src/plugins/beautifier/meson.build b/src/plugins/beautifier/meson.build
index af37614f2..c6f28c37d 100644
--- a/src/plugins/beautifier/meson.build
+++ b/src/plugins/beautifier/meson.build
@@ -14,6 +14,20 @@ plugin_beautifier_resources = gnome.compile_resources(
   c_name: 'gbp_beautifier',
 )
 
+beautifiers = [
+  'autopep8',
+  'tidy',
+  'uncrustify',
+  'xmllint',
+]
+# Only indicate the missing beautifiers at build time, but don't require them strongly.
+foreach beautifier : beautifiers
+  program = find_program(beautifier, required: false)
+  if not program.found()
+    message('Please install beautifier @0@ as runtime dependency'.format(beautifier))
+  endif
+endforeach
+
 plugins_sources += plugin_beautifier_resources
 
 endif