Only alias the symbol for non macOS targets

- Xcode uses CoreFoundation/Base.subproj/SymbolAliases to set the
  symbol.

Author: spevans

CoreFoundation/Base.subproj/CFInternal.h

@@ -349,7 +349,12 @@ CF_EXPORT void * __CFConstantStringClassReferencePtr;
 
 #if DEPLOYMENT_RUNTIME_SWIFT
 
+#if TARGET_OS_MAC
+CF_EXPORT void *__CFConstantStringClassReference[];
+#else
 CF_EXPORT void *__CFConstantStringClassReference[] asm("_T010Foundation19_NSCFConstantStringCN");
+#endif
+
 
 #if __CF_BIG_ENDIAN__
 #define CF_CONST_STRING_INFO {0x00, 0x00, 0x07, 0xc8}