Declare __cxa_new_handler as extern "C", or it declares a new variable

Reverts change from r219012 to fix ABI incompatibility. Let's not worry
about the GCC warning here.

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@235013 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed