Mojo: Move common/basic functions declarations from mojo/public/c/system/core.h to .../functions.h.

mojo/public/c/system/types.h

Index: mojo/public/c/system/types.h
diff --git a/mojo/public/c/system/types.h b/mojo/public/c/system/types.h
index 03b2c6b7c05a903f41e0d4fb1f01f30e650f4e93..da4577a60c1f4624341f084357a9473e19b39c32 100644
--- a/mojo/public/c/system/types.h
+++ b/mojo/public/c/system/types.h
@@ -4,16 +4,14 @@
 
 // This file contains types and constants/macros common to different Mojo system
 // APIs.
+//
+// Note: This header should be compilable as C.
 
 #ifndef MOJO_PUBLIC_C_SYSTEM_TYPES_H_
 #define MOJO_PUBLIC_C_SYSTEM_TYPES_H_
 
-// Note: This header should be compilable as C.
-
 #include <stdint.h>
 
-// Types/constants -------------------------------------------------------------
-
 // TODO(vtl): Notes: Use of undefined flags will lead to undefined behavior
 // (typically they'll be ignored), not necessarily an error.