[gnome-session] build: Use meson 0.43.0 features

[Iñigo Martínez <inigomartinez src gnome org>]

commit b059c2862abb8c29127620606bf8c45f281a97b0
Author: Iñigo Martínez <inigomartinez gmail com>
Date:   Fri Nov 17 10:40:59 2017 +0100

    build: Use meson 0.43.0 features
    
    meson 0.43.0 comes with a new function in the compiler's object
    called get_supported_arguments, which allows checking multiple
    options at once.
    
    This patch takes advantage of this new feature.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790486

 meson.build |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)
---
diff --git a/meson.build b/meson.build
index ba44d02..5fcbd88 100644
--- a/meson.build
+++ b/meson.build
@@ -85,11 +85,7 @@ if session_debug
     '-Wstrict-prototypes'
   ]
 
-  foreach cflag: test_cflags
-    if cc.has_argument(cflag)
-      compiler_flags += [cflag]
-    endif
-  endforeach
+  compiler_flags += cc.get_supported_arguments(test_cflags)
 endif
 
 add_project_arguments(common_flags + compiler_flags, language: 'c')