Merge pull request #2142 from jceipek/fix-objc_allocateClassPair

Fix signature for `objc_allocateClassPair` and add `objc_registerClassPair` to enable Objective-C subclassing

core/runtime/procs_darwin.odin

@@ -12,7 +12,7 @@ objc_SEL :: ^intrinsics.objc_selector
 foreign Foundation {
 	objc_lookUpClass :: proc "c" (name: cstring) -> objc_Class ---
 	sel_registerName :: proc "c" (name: cstring) -> objc_SEL ---
-	objc_allocateClassPair :: proc "c" (superclass: objc_Class, name: cstring, extraBytes: uint) ---
+	objc_allocateClassPair :: proc "c" (superclass: objc_Class, name: cstring, extraBytes: uint) -> objc_Class ---
 
 	objc_msgSend        :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) ---
 	objc_msgSend_fpret  :: proc "c" (self: objc_id, op: objc_SEL, #c_vararg args: ..any) -> f64 ---

vendor/darwin/Foundation/objc.odin

@@ -10,7 +10,8 @@ IMP :: proc "c" (object: id, sel: SEL, #c_vararg args: ..any) -> id
 foreign Foundation {
 	objc_lookUpClass       :: proc "c" (name: cstring) -> Class ---
 	sel_registerName       :: proc "c" (name: cstring) -> SEL ---
-	objc_allocateClassPair :: proc "c" (superclass: Class, name: cstring, extraBytes: uint) ---
+	objc_allocateClassPair :: proc "c" (superclass : Class, name : cstring, extraBytes : c.size_t) -> Class ---
+	objc_registerClassPair :: proc "c" (cls : Class) ---
 
 	class_addMethod :: proc "c" (cls: Class, name: SEL, imp: IMP, types: cstring) -> BOOL ---
 	class_getInstanceMethod :: proc "c" (cls: Class, name: SEL) -> Method ---