Summary:
Use _LIBCPP_MSVCRT_LIKE while configuring ELAST, so MinGW gets the same
configuration as MSVC.
Reviewers: compnerd, srhines, danalbert, mstorsjo
Subscribers: christof, ldionne, cfe-commits
Differential Revision: https://reviews.llvm.org/D48731
llvm-svn: 335916