Work around reparse point stat issues

In theory, p_stat should never return an S_ISLNK result, but due
to the current implementation on Windows with mount points it is
possible that it will.  For now, work around that by allowing a
link in the path to a directory being created.  If it is really a
problem, then the issue will be caught on the next iteration of
the loop, but typically this will be the right thing to do.

src/fileops.c

@@ -348,7 +348,8 @@ int git_futils_mkdir(
 			int tmp_errno = errno;
 
 			/* ignore error if directory already exists */
-			if (p_stat(make_path.ptr, &st) < 0 || !S_ISDIR(st.st_mode)) {
+			if (p_stat(make_path.ptr, &st) < 0 ||
+				!(S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode))) {
 				errno = tmp_errno;
 				giterr_set(GITERR_OS, "Failed to make directory '%s'", make_path.ptr);
 				goto done;