[gnome-session] main: allow users to override QT_QPA_PLATFORMTHEME

[Ray Strode <halfline src gnome org>]

commit ce4208add3b49d440e0c418229774dd802ee6b87
Author: Ray Strode <rstrode redhat com>
Date:   Thu Mar 31 21:55:55 2016 -0400

    main: allow users to override QT_QPA_PLATFORMTHEME
    
    commit 971baf2e225abc5a67bd0c149f4cbfdb0ef8c549 added
    code to make Qt applications look like GNOME ones.
    
    That makes it impossible for users to use custom
    platform themes though.
    
    This commit addresses the problem by only setting
    QT_QPA_PLATFORMTHEME if it isn't already set.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762681

 gnome-session/main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gnome-session/main.c b/gnome-session/main.c
index 9f3ca0f..615b4ce 100644
--- a/gnome-session/main.c
+++ b/gnome-session/main.c
@@ -415,7 +415,9 @@ main (int argc, char **argv)
 
         /* Tell Qt to try to make Qt applications look like gnome
          */
-        gsm_util_setenv ("QT_QPA_PLATFORMTHEME", "qgnomeplatform");
+        if (g_getenv ("QT_QPA_PLATFORMTHEME") == NULL) {
+                gsm_util_setenv ("QT_QPA_PLATFORMTHEME", "qgnomeplatform");
+        }
 
         /* hack to fix keyring until we can reorder things in 3.20
          * https://bugzilla.gnome.org/show_bug.cgi?id=738205