Remove core:os dependency from base:runtime; change to base:intrinsics

base/runtime/os_specific_darwin.odin

@@ -1,12 +1,25 @@
 //+build darwin
+//+private
 package runtime
 
-import "core:intrinsics"
+foreign import libc "system:System.framework"
+
+foreign libc {
+	@(link_name="__stderrp")
+	_stderr: rawptr
+
+	@(link_name="fwrite")
+	_fwrite :: proc(ptr: rawptr, size: uint, nmemb: uint, stream: rawptr) -> uint ---
+
+	@(link_name="__error")
+	_get_errno :: proc() -> ^i32 ---
+}
 
 _os_write :: proc "contextless" (data: []byte) -> (int, _OS_Errno) {
-	ret := intrinsics.syscall(0x2000004, 1, uintptr(raw_data(data)), uintptr(len(data)))
-	if ret < 0 {
-		return 0, _OS_Errno(-ret)
+	ret := _fwrite(raw_data(data), 1, len(data), _stderr)
+	if ret < len(data) {
+		err := _get_errno()
+		return int(ret), _OS_Errno(err^ if err != nil else 0)
 	}
 	return int(ret), 0
 }