Pure C winform on OS X Apple Silicon

// based on https://stackoverflow.com/a/59596600/834108
// Minimal Pure C code to create a window in Cocoa
// Adapted to work on ARM64

// $ clang minimal.c -framework Cocoa -o minimal.app

#include <objc/runtime.h>
#include <objc/message.h>

#include <Carbon/Carbon.h>

#define cls objc_getClass
#define sel sel_getUid
#define msg ((id (*)(id, SEL))objc_msgSend)
#define msg_int ((id (*)(id, SEL, int))objc_msgSend)
#define msg_id  ((id (*)(id, SEL, id))objc_msgSend)
#define msg_ptr ((id (*)(id, SEL, void*))objc_msgSend)
#define msg_cls ((id (*)(Class, SEL))objc_msgSend)
#define msg_cls_chr ((id (*)(Class, SEL, char*))objc_msgSend)

// poor man's bindings!
typedef enum NSApplicationActivationPolicy {
    NSApplicationActivationPolicyRegular   = 0,
    NSApplicationActivationPolicyAccessory = 1,
    NSApplicationActivationPolicyERROR     = 2,
} NSApplicationActivationPolicy;

typedef enum NSWindowStyleMask {
    NSWindowStyleMaskBorderless     = 0,
    NSWindowStyleMaskTitled         = 1 << 0,
    NSWindowStyleMaskClosable       = 1 << 1,
    NSWindowStyleMaskMiniaturizable = 1 << 2,
    NSWindowStyleMaskResizable      = 1 << 3,
} NSWindowStyleMask;

typedef enum NSBackingStoreType {
    NSBackingStoreBuffered = 2,
} NSBackingStoreType;

int main(int argc, char *argv[])
{
    id app = msg_cls(cls("NSApplication"), sel("sharedApplication"));
    msg_int(app, sel("setActivationPolicy:"), NSApplicationActivationPolicyRegular);
    struct CGRect frameRect = {0, 0, 600, 500};

    id window = ((id (*)(id, SEL, struct CGRect, int, int, int))objc_msgSend)(
        msg_cls(cls("NSWindow"), sel("alloc")),
        sel("initWithContentRect:styleMask:backing:defer:"),
        frameRect,
        NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable,
        NSBackingStoreBuffered,
        false
    );
    msg_id(window, sel("setTitle:"), msg_cls_chr(cls("NSString"), sel("stringWithUTF8String:"), "Pure C App"));
    msg_ptr(window, sel("makeKeyAndOrderFront:"), nil);
    msg_int(app, sel("activateIgnoringOtherApps:"), true);
    msg(app, sel("run"));
}