REGRESSION (r140912): Broke specifying non-trivial ARCHS value to make / build-webkit

REGRESSION (r140912): Broke specifying non-trivial ARCHS value to make / build-webkit
https://bugs.webkit.org/show_bug.cgi?id=108028

Patch by David Farler <dfarler@apple.com> on 2013-01-27
Reviewed by Dan Bernstein.

.:

* Makefile: Reverted.
* Makefile.shared: Reverted.
* Source/Makefile: Reverted.

Tools:

* DumpRenderTree/Makefile: Reverted.
* Makefile: Reverted.
* Scripts/webkitdirs.pm: Reverted.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@140939 268f45cc-cd09-0410-ab3c-d52691b4dbfc