[gnome-builder] flatpak: allow overriding PATH

[Christian Hergert <chergert src gnome org>]

commit 3dd0ab427744a1b83da4e8b3c97cacd9794fe749
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jan 16 00:47:07 2018 -0800

    flatpak: allow overriding PATH
    
    We want to allow PATH to be overridden so that new PATH parts
    can be appended. Such is used by SDK extensions.

 src/plugins/flatpak/gbp-flatpak-subprocess-launcher.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)
---
diff --git a/src/plugins/flatpak/gbp-flatpak-subprocess-launcher.c 
b/src/plugins/flatpak/gbp-flatpak-subprocess-launcher.c
index fa7426783..8e8359f59 100644
--- a/src/plugins/flatpak/gbp-flatpak-subprocess-launcher.c
+++ b/src/plugins/flatpak/gbp-flatpak-subprocess-launcher.c
@@ -40,15 +40,6 @@ gbp_flatpak_subprocess_launcher_spawn (IdeSubprocessLauncher  *launcher,
   g_assert (IDE_IS_SUBPROCESS_LAUNCHER (launcher));
   g_assert (!cancellable || G_IS_CANCELLABLE (cancellable));
 
-  /*
-   * Don't allow PATH to be set when traversing "flatpak build" from the
-   * default IdeSubprocessLauncher. We need to ensure that /app/bin is before
-   * /usr/bin so that we are similar to "flatpak run org.gnome.Sdk" and that
-   * the developers tooling can override /usr/.
-   */
-  if (ide_subprocess_launcher_get_clear_env (launcher))
-    ide_subprocess_launcher_setenv (launcher, "PATH", "/app/bin:/usr/bin", TRUE);
-
   /*
    * The "flatpak build" command will filter out all of our environment variables
    * from the subprocess. So we need to look at our configured environment and
@@ -92,6 +83,8 @@ gbp_flatpak_subprocess_launcher_spawn (IdeSubprocessLauncher  *launcher,
           if (!g_strv_contains (argv, arg))
             ide_subprocess_launcher_insert_argv (launcher, argpos, arg);
         }
+
+      ide_subprocess_launcher_setenv (launcher, "PATH", NULL, TRUE);
     }
 
   ret = IDE_SUBPROCESS_LAUNCHER_CLASS (gbp_flatpak_subprocess_launcher_parent_class)->spawn (launcher, 
cancellable, error);
@@ -110,6 +103,7 @@ gbp_flatpak_subprocess_launcher_class_init (GbpFlatpakSubprocessLauncherClass *k
 static void
 gbp_flatpak_subprocess_launcher_init (GbpFlatpakSubprocessLauncher *self)
 {
+  ide_subprocess_launcher_setenv (IDE_SUBPROCESS_LAUNCHER (self), "PATH", "/app/bin:/usr/bin", TRUE);
 }
 
 IdeSubprocessLauncher *