Fix build with MingW

Fix wrong export/import flags in inlined methods.

Use normal GCC inline asm instead of _ReadWriteBarrier.

Change-Id: Iba6b923be383777f2807d84349044dbe5a22eb57
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>
[Qt] Update sync.profile https://bugs.webkit.org/show_bug.cgi?id=121295

Reviewed by Simon Hausmann.

Ensure we let the dependencies pick the right branch instead of always
master and list all the dependencies we need on all platforms.

* Source/sync.profile:

Change-Id: Ia6f2d55911eb18c4ecacac017439afe78db5f17c
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@155694 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>