kHasRtti

Summary: [Folly] `kHasRtti` to parallel `FOLLY_HAS_RTTI`.

Reviewed By: Orvid

Differential Revision: D14129217

fbshipit-source-id: ce60fd0b47c64c19b515d21db55aa88ba37ca637

folly/Portability.h

@@ -362,6 +362,10 @@ using namespace FOLLY_GFLAGS_NAMESPACE;
 #define FOLLY_HAS_RTTI 0
 #endif
 
+namespace folly {
+constexpr bool const kHasRtti = FOLLY_HAS_RTTI;
+} // namespace folly
+
 #if defined(__APPLE__) || defined(_MSC_VER)
 #define FOLLY_STATIC_CTOR_PRIORITY_MAX
 #else

folly/detail/StaticSingletonManager.h

@@ -87,7 +87,7 @@ class StaticSingletonManagerWithRtti {
 };
 
 using StaticSingletonManager = std::conditional_t<
-    FOLLY_HAS_RTTI,
+    kHasRtti,
     StaticSingletonManagerWithRtti,
     StaticSingletonManagerSansRtti>;