[PATCH] [compiler-rt][builtins] CTest to execute builtins testsuite

[Faraz Shahbazker]

>>! In D4251#10, @sgundapa wrote:
> We want to build the unit tests when invoked with "check-builtins". Isn't it?
That is exactly what this patch does.

> I am writing the lit cfg files for test/builtins and will upload it when I am done testing it.
Great! In that case I won't bother doing a second revision. Should I mark this as abandoned?

http://reviews.llvm.org/D4251