+#define IS_UNIX_DIR_SEPARATOR(c) IS_DIR_SEPARATOR_1 (0, c)
+#define IS_UNIX_ABSOLUTE_PATH(f) IS_ABSOLUTE_PATH_1 (0, f)
+
+/* Note that when DOS_BASED is true, IS_ABSOLUTE_PATH accepts d:foo as
+ well, although it is only semi-absolute. This is because the users
+ of IS_ABSOLUTE_PATH want to know whether to prepend the current
+ working directory to a file name, which should not be done with a
+ name like d:foo. */
+#define IS_ABSOLUTE_PATH_1(dos_based, f) \
+ (IS_DIR_SEPARATOR_1 (dos_based, (f)[0]) \
+ || HAS_DRIVE_SPEC_1 (dos_based, f))