[mutter/wip/carlosg/frames-client] core: Add fallback location for the mutter-x11-frames executable

[Carlos Garnacho <carlosg src gnome org>]

commit a051196c25365f888787a539aaf86c9b7da5b98b
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Sep 17 10:28:41 2022 +0200

    core: Add fallback location for the mutter-x11-frames executable
    
    Typically this will be installed in libexecdir and run from there, but
    this requires "ninja install" before "ninja test", which is not ideal.
    
    Add a fallback specific to the situation of meson tests, so that the
    frames client is executed from the builddir instead. In order to
    avoid disk seeks checking for file existence, and envvars to tweak
    Mutter behavior, this is only done as a last resort, the installed
    executable in libexecdir is still preferred.

 src/core/frame.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/src/core/frame.c b/src/core/frame.c
index 132e71227e..88793008b7 100644
--- a/src/core/frame.c
+++ b/src/core/frame.c
@@ -534,8 +534,21 @@ on_x11_display_setup (MetaDisplay *display,
   proc = g_subprocess_launcher_spawnv (launcher, args, &error);
   if (error)
     {
-      g_warning ("Could not launch X11 frames client: %s", error->message);
-      return;
+      if (g_error_matches (error, G_SPAWN_ERROR, G_SPAWN_ERROR_NOENT))
+        {
+          /* Fallback case for uninstalled tests, relies on CWD being
+           * the builddir, as it is the case during "ninja test".
+           */
+          g_clear_error (&error);
+          args[0] = "./src/frames/mutter-x11-frames";
+          proc = g_subprocess_launcher_spawnv (launcher, args, &error);
+        }
+
+      if (error)
+        {
+          g_warning ("Could not launch X11 frames client: %s", error->message);
+          return;
+        }
     }
 
   g_subprocess_wait_async (proc, NULL, on_frames_died, display);