Rewrite init app in C, introduce MSL (MOP3 System Library)

libmsl/amd64/syscall.h

@@ -0,0 +1,8 @@
+#ifndef _LIBMSL_AMD64_SYSCALL_H
+#define _LIBMSL_AMD64_SYSCALL_H
+
+#include <stdint.h>
+
+int msl_amd64_syscall (int syscall_num, uintptr_t a1, uintptr_t a2, uintptr_t a3, uintptr_t a4, uintptr_t a5, uintptr_t a6);
+
+#endif // _LIBMSL_AMD64_SYSCALL_H