core: Support systems without thread-local storage
core: Support systems without thread-local storage

XCode 3.1 ships with an old version of gcc that does not support TLS.
There are Waffle users that require support for XCode 3.1.

Tested on Mac OS with XCode 3.1 gcc and XCode 4.6.2 clang by Nigel.

Tested-by: Nigel Stewart <ab02c6caead0f3530a28ee6ec7b0d1c00356e99e@gmail.com>
Signed-off-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>

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