halt on unexpected syscalls

`Expects()` doesn't actually shut down the service, causing an infinite
loop of strace errors

Author: mazunki

src/musl/common.hpp

@@ -74,6 +74,7 @@ template<typename Fn, typename ...Args>
 inline auto strace(Fn func, [[maybe_unused]]const char* name, Args&&... args) {
   if (!kernel::state().allow_syscalls) {
     fprintf(stderr, "Syscalls not allowed here. Unexpected call to %s - terminating\n", name);
+    os::halt();
     Expects(kernel::state().allow_syscalls);
   }