parsers: don't ask about the exec bit on platforms that don't have it

Otherwise the compiler gets quite sad.

Differential Revision: https://phab.mercurial-scm.org/D11711

mercurial/cext/parsers.c

@@ -260,11 +260,16 b' static PyObject *dirstate_item_v2_data(d'
 {
 	int flags = self->flags;
 	int mode = dirstate_item_c_v1_mode(self);
+#ifdef S_IXUSR
+	/* This is for platforms with an exec bit */
 	if ((mode & S_IXUSR) != 0) {
 		flags |= dirstate_flag_mode_exec_perm;
 	} else {
 		flags &= ~dirstate_flag_mode_exec_perm;
 	}
+#else
+	flags &= ~dirstate_flag_mode_exec_perm;
+#endif
 	if (S_ISLNK(mode)) {
 		flags |= dirstate_flag_mode_is_symlink;
 	} else {