Check that __MAC_OS_X_VERSION_MIN_REQUIRED is defined before checking

whether it is too old.

llvm-svn: 344856

clang-tools-extra/unittests/clangd/JSONTransportTests.cpp

@@ -19,7 +19,9 @@ namespace {
 
 // No fmemopen on windows or on versions of MacOS X earlier than 10.13, so we
 // can't easily run this test.
-#if !(defined(WIN32) || __MAC_OS_X_VERSION_MIN_REQUIRED < 101300)
+#if !(defined(WIN32) || \
+      (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && \
+       __MAC_OS_X_VERSION_MIN_REQUIRED < 101300))
 
 // Fixture takes care of managing the input/output buffers for the transport.
 class JSONTransportTest : public ::testing::Test {