B_USE_BUILTIN_ATOMIC_FUNCTIONS is defined most atomic_*() functions are
redefined as macros using the built-ins directly.
* Enabled that feature for the x86 build. Might work on other platforms as
well, but that needs to be tested.
No significant speedup for the -j8 Haiku image build.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35018 a95241bf-73f2-0310-859d-f6bbb57e9c96
4f7b2c67b0