Move the dispatch_main_async_safe into internal macros, since it's used in implementation files but not headers

SDWebImageCompat.h should only contain the macros support used in header

SDWebImage/Private/SDInternalMacros.h

@@ -9,6 +9,15 @@
 #import <Foundation/Foundation.h>
 #import "metamacros.h"
 
+#ifndef dispatch_main_async_safe
+#define dispatch_main_async_safe(block)\
+if (dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL) == dispatch_queue_get_label(dispatch_get_main_queue())) {\
+    block();\
+} else {\
+    dispatch_async(dispatch_get_main_queue(), block);\
+}
+#endif
+
 #ifndef SD_LOCK
 #define SD_LOCK(lock) dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
 #endif

SDWebImage/SDWebImageCompat.h

@@ -84,12 +84,3 @@
 #ifndef NS_OPTIONS
 #define NS_OPTIONS(_type, _name) enum _name : _type _name; enum _name : _type
 #endif
-
-#ifndef dispatch_main_async_safe
-#define dispatch_main_async_safe(block)\
-    if (dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL) == dispatch_queue_get_label(dispatch_get_main_queue())) {\
-        block();\
-    } else {\
-        dispatch_async(dispatch_get_main_queue(), block);\
-    }
-#endif