[gnome-control-center] common: Replace ifdefs with #pragma once

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 1ea6941fb8350d14a99845ba0d826aca0a392683
Author: Robert Ancell <robert ancell canonical com>
Date:   Thu Nov 21 20:34:28 2019 +1300

    common: Replace ifdefs with #pragma once

 panels/common/meson.build | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/panels/common/meson.build b/panels/common/meson.build
index fc254b1df..2d5121297 100644
--- a/panels/common/meson.build
+++ b/panels/common/meson.build
@@ -8,10 +8,10 @@ enums_header = files('gsd-device-manager.h')
 common_sources += gnome.mkenums(
   enums + '.h',
   sources: enums_header,
-  fhead: '#ifndef GSD_COMMON_ENUMS_H\n#define GSD_COMMON_ENUMS_H\n\n#include 
<glib-object.h>\n\nG_BEGIN_DECLS\n',
+  fhead: '#pragma once\n\n#include <glib-object.h>\n\nG_BEGIN_DECLS\n',
   fprod: '/* enumerations from "@filename@" */\n',
   vhead: 'GType @enum_name@_get_type (void) G_GNUC_CONST;\n#define GSD_TYPE_@ENUMSHORT@ 
(@enum_name@_get_type())\n',
-  ftail: 'G_END_DECLS\n\n#endif /* !GSD_COMMON_ENUMS_H */'
+  ftail: 'G_END_DECLS\n'
 )
 
 common_sources += gnome.mkenums(