From 408597e5bc528477608785709ba3fa67ef64823f Mon Sep 17 00:00:00 2001
From: Igor Sugak <sugak@fb.com>
Date: Sun, 8 Nov 2015 00:32:52 -0800
Subject: [PATCH] folly/portability: add clang version check

Summary: Define `__CLANG_PREREQ` macro to check version of clang.

Reviewed By: yfeldblum

Differential Revision: D2630325

fb-gh-sync-id: 3d666e554e8ddfc2c1fecd439aaf93f015829025
---
 folly/Portability.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/folly/Portability.h b/folly/Portability.h
index 594ab9aa..bdac6cc3 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -174,6 +174,18 @@
 namespace std { typedef ::max_align_t max_align_t; }
 #endif
 
+// portable version check for clang
+#ifndef __CLANG_PREREQ
+# if defined __clang__ && defined __clang_major__ && defined __clang_minor__
+/* nolint */
+#  define __CLANG_PREREQ(maj, min) \
+    ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
+# else
+/* nolint */
+#  define __CLANG_PREREQ(maj, min) 0
+# endif
+#endif
+
 /* Platform specific TLS support
  * gcc implements __thread
  * msvc implements __declspec(thread)
-- 
2.34.1