makedev is a macro on several systems.

Author: maatta

ext/posix/posix.c

@@ -698,7 +698,7 @@ PHP_FUNCTION(posix_mknod)
 				"expects argument 4 to be non-zero for POSIX_S_IFCHR and POSIX_S_IFBLK");
 			RETURN_FALSE;
 		} else {
-#ifdef HAVE_MAKEDEV
+#if defined(HAVE_MAKEDEV) || defined(makedev)
 			php_dev = makedev(major, minor);
 #else
 			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Can not create a block or character device, creating a normal file instead");