[libc++] Use _LIBCPP_ABI_MICROSOFT instead of _MSC_VER
authorShoaib Meenai <smeenai@fb.com>
Wed, 19 Apr 2017 20:11:04 +0000 (20:11 +0000)
committerShoaib Meenai <smeenai@fb.com>
Wed, 19 Apr 2017 20:11:04 +0000 (20:11 +0000)
commit3698889a7ba10a1b9f3b0d33c3e25117561c4554
tree5f6dc63793a23cfdb78849390359955dd2a33697
parenta364f09f185f65c3d23d93a313177ca8da3d7877
[libc++] Use _LIBCPP_ABI_MICROSOFT instead of _MSC_VER

_LIBCPP_ABI_MICROSOFT is more appropriate to use here, since the
conditionals are controlling Microsoft mangling. It wasn't used
originally since it didn't exist at the time.

llvm-svn: 300743
libcxx/src/iostream.cpp