Fix windows build, patch by Howard Su.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74697 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Errno.cpp b/lib/System/Errno.cpp
index f4e3a88..d046aba 100644
--- a/lib/System/Errno.cpp
+++ b/lib/System/Errno.cpp
@@ -47,10 +47,10 @@
# else
strerror_r(errnum,buffer,MaxErrStrLen-1);
# endif
-#elif HAVE_STRERROR_S // Windows.
+#elif defined(HAVE_STRERROR_S) // Windows.
if (errnum)
strerror_s(buffer, errnum);
-#elif HAVE_STRERROR
+#elif defined(HAVE_STRERROR)
// Copy the thread un-safe result of strerror into
// the buffer as fast as possible to minimize impact
// of collision of strerror in multiple threads.