Rename libc++ internal templates __is_void, __is_integral, __is_floating_point, __is_pointer, __is_function_imp, __is_function, __is_member_function_pointer, __is_member_pointer, __is_signed_impl, __is_signed, __is_unsigned_impl, __is_unsigned to __libcpp_is_XXX, because some compilers have decided that __is_XXX are keywords. No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@199184 91177308-0d34-0410-b5e6-96231b3b80d8