Header only file doesn't need c++ guard

include/ucore/sarena.h

@@ -4,9 +4,6 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <assert.h>
-#ifdef __cplusplus
-extern "C" {
-#endif
 
 /** @file
  * Static arena allocator.
@@ -177,8 +174,4 @@ static inline size_t uc_sar_available(const UCSArena *arena)
     return uc_sar_size(arena) - uc_sar_used(arena);
 }
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif