The cmake check for whether libatomic could be used had been
unconditionally setting the result to false. Which was somewhat
fortunate, because the prerequisite check for whether it was *needed*
was always claiming it was, even if it was not.
However, this made platforms where libatomic is actually necessary
fail to link.
Differential Revision: http://reviews.llvm.org/D10453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239819 91177308-0d34-0410-b5e6-96231b3b80d8
It is possible for the atomic routines to be provided by the compiler without
requiring any additional libraries. Check if that is the case before checking
for a library.
Patch by Matt Glazar!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230452 91177308-0d34-0410-b5e6-96231b3b80d8
