[gvfs] Revert "build: Avoid extra variable on compiler flag checking"

[Ondrej Holy <oholy src gnome org>]

commit 2b0a4051fba0207b78ce764d4a2faccaf7e889e4
Author: Ondrej Holy <oholy redhat com>
Date:   Mon Jan 7 17:44:09 2019 +0100

    Revert "build: Avoid extra variable on compiler flag checking"
    
    This reverts commit a644c8763e1ed8a97fb1115046903d0c2583b8d5.

 meson.build | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index da0d731d..d5916082 100644
--- a/meson.build
+++ b/meson.build
@@ -213,14 +213,16 @@ endforeach
 common_flags = ['-DHAVE_CONFIG_H']
 
 if gvfs_debug
-  common_flags += cc.get_supported_arguments([
+  test_cflags = [
     '-Wcast-align',
     '-Wmissing-declarations',
     '-Wmissing-prototypes',
     '-Wnested-externs',
     '-Wno-sign-compare',
     '-Wno-strict-aliasing',
-  ])
+  ]
+
+  common_flags += cc.get_supported_arguments(test_cflags)
 endif
 
 add_project_arguments(common_flags, language: 'c')