Add support for JavaScriptCore

[ialex32x]

Reduce the application footprint by utilizing the JavaScriptCore.framework bundled with macOS/iOS, and support remote debugging in Safari.

[ialex32x]

JS_EXPORT void JSGlobalContextSetUnhandledRejectionCallback(JSGlobalContextRef ctx, JSObjectRef function, JSValueRef* exception) JSC_API_AVAILABLE(macos(10.15.4), ios(13.4));

JS_EXPORT JSStringRef JSContextCreateBacktrace(JSContextRef ctx, unsigned maxStackSize) JSC_API_AVAILABLE(macos(10.6), ios(7.0));

JS_EXPORT void JSContextGroupSetExecutionTimeLimit(JSContextGroupRef group, double limit, JSShouldTerminateCallback callback, void* context) JSC_API_AVAILABLE(macos(10.6), ios(7.0));

JS_EXPORT JSGlobalContextRef JSObjectGetGlobalContext(JSObjectRef object);

JS_EXPORT void JSContextGroupAddHeapFinalizer(JSContextGroupRef, JSHeapFinalizer, void *userData);