Use __wasi_fd_is_valid in fstatat.c

Author: kleisauke

system/lib/libc/musl/src/stat/fstatat.c

@@ -79,7 +79,11 @@ static int fstatat_kstat(int fd, const char *restrict path, struct stat *restric
 
 	if (flag==AT_EMPTY_PATH && fd>=0 && !*path) {
 		ret = __syscall(SYS_fstat, fd, &kst);
+#ifdef __EMSCRIPTEN__
+		if (ret==-EBADF && __wasi_fd_is_valid(fd)) {
+#else
 		if (ret==-EBADF && __syscall(SYS_fcntl, fd, F_GETFD)>=0) {
+#endif
 			ret = __syscall(SYS_fstatat, fd, path, &kst, flag);
 			if (ret==-EINVAL) {
 				char buf[15+3*sizeof(int)];