Add FOLLY_HAS_FEATURE and use it

Summary:
[Folly] Add `FOLLY_HAS_FEATURE` and use it.

Use it in the definitions of `FOLLY_SANITIZE_ADDRESS` and `FOLLY_SANITIZE_THREAD`.

Reviewed By: meyering

Differential Revision: D5496915

fbshipit-source-id: e272137ad8ba891e64fc98444edf573115764ee2

folly/CPortability.h

@@ -51,15 +51,15 @@
 #define FOLLY_HAS_BUILTIN(...) 0
 #endif
 
+#if defined(__has_feature)
+#define FOLLY_HAS_FEATURE(...) __has_feature(__VA_ARGS__)
+#else
+#define FOLLY_HAS_FEATURE(...) 0
+#endif
+
 /* Define a convenience macro to test when address sanitizer is being used
  * across the different compilers (e.g. clang, gcc) */
-#if defined(__clang__)
-# if __has_feature(address_sanitizer)
-#  define FOLLY_SANITIZE_ADDRESS 1
-# endif
-#elif defined (__GNUC__) && \
-      (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 8)) || (__GNUC__ >= 5)) && \
-      __SANITIZE_ADDRESS__
+#if FOLLY_HAS_FEATURE(address_sanitizer) || __SANITIZE_ADDRESS__
 # define FOLLY_SANITIZE_ADDRESS 1
 #endif
 
@@ -89,11 +89,7 @@
 
 /* Define a convenience macro to test when thread sanitizer is being used
  * across the different compilers (e.g. clang, gcc) */
-#if defined(__clang__)
-# if __has_feature(thread_sanitizer)
-#  define FOLLY_SANITIZE_THREAD 1
-# endif
-#elif defined(__GNUC__) && __SANITIZE_THREAD__
+#if FOLLY_HAS_FEATURE(thread_sanitizer) || __SANITIZE_THREAD__
 # define FOLLY_SANITIZE_THREAD 1
 #endif