-#define IS_DIR_SEPARATOR(c) ((c) == '/' || (c) == '\\')
-/* Note that 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(f) (IS_DIR_SEPARATOR((f)[0]) || (((f)[0]) && ((f)[1] == ':')))
-#define FILENAME_CMP(s1, s2) strcasecmp(s1, s2)
+#if defined(__MSDOS__) || defined(_WIN32) || defined(__OS2__) || defined (__CYGWIN__)
+# ifndef HAVE_DOS_BASED_FILE_SYSTEM
+# define HAVE_DOS_BASED_FILE_SYSTEM 1
+# endif
+# ifndef HAVE_CASE_INSENSITIVE_FILE_SYSTEM
+# define HAVE_CASE_INSENSITIVE_FILE_SYSTEM 1
+# endif
+# define HAS_DRIVE_SPEC(f) HAS_DOS_DRIVE_SPEC (f)
+# define IS_DIR_SEPARATOR(c) IS_DOS_DIR_SEPARATOR (c)
+# define IS_ABSOLUTE_PATH(f) IS_DOS_ABSOLUTE_PATH (f)
+#else /* not DOSish */
+# if defined(__APPLE__)
+# ifndef HAVE_CASE_INSENSITIVE_FILE_SYSTEM
+# define HAVE_CASE_INSENSITIVE_FILE_SYSTEM 1
+# endif
+# endif /* __APPLE__ */
+# define HAS_DRIVE_SPEC(f) (0)
+# define IS_DIR_SEPARATOR(c) IS_UNIX_DIR_SEPARATOR (c)
+# define IS_ABSOLUTE_PATH(f) IS_UNIX_ABSOLUTE_PATH (f)
+#endif
+
+#define IS_DIR_SEPARATOR_1(dos_based, c) \
+ (((c) == '/') \
+ || (((c) == '\\') && (dos_based)))
+
+#define HAS_DRIVE_SPEC_1(dos_based, f) \
+ ((f)[0] && ((f)[1] == ':') && (dos_based))
+
+/* Remove the drive spec from F, assuming HAS_DRIVE_SPEC (f).
+ The result is a pointer to the remainder of F. */
+#define STRIP_DRIVE_SPEC(f) ((f) + 2)
+
+#define IS_DOS_DIR_SEPARATOR(c) IS_DIR_SEPARATOR_1 (1, c)
+#define IS_DOS_ABSOLUTE_PATH(f) IS_ABSOLUTE_PATH_1 (1, f)
+#define HAS_DOS_DRIVE_SPEC(f) HAS_DRIVE_SPEC_1 (1, f)
+
+#define IS_UNIX_DIR_SEPARATOR(c) IS_DIR_SEPARATOR_1 (0, c)
+#define IS_UNIX_ABSOLUTE_PATH(f) IS_ABSOLUTE_PATH_1 (0, f)