+#if @GNULIB_MBSSEP@
+/* Search the next delimiter (multibyte character listed in the character
+ string DELIM) starting at the character string *STRINGP.
+ If one is found, overwrite it with a NUL, and advance *STRINGP to point
+ to the next multibyte character after it. Otherwise, set *STRINGP to NULL.
+ If *STRINGP was already NULL, nothing happens.
+ Return the old value of *STRINGP.
+
+ This is a variant of mbstok_r() that supports empty fields.
+
+ Caveat: It modifies the original string.
+ Caveat: These functions cannot be used on constant strings.
+ Caveat: The identity of the delimiting character is lost.
+
+ See also mbstok_r(). */
+extern char * mbssep (char **stringp, const char *delim);
+#endif
+
+#if @GNULIB_MBSTOK_R@
+/* Parse the character string STRING into tokens separated by characters in
+ the character string DELIM.
+ If STRING is NULL, the saved pointer in SAVE_PTR is used as
+ the next starting point. For example:
+ char s[] = "-abc-=-def";
+ char *sp;
+ x = mbstok_r(s, "-", &sp); // x = "abc", sp = "=-def"
+ x = mbstok_r(NULL, "-=", &sp); // x = "def", sp = NULL
+ x = mbstok_r(NULL, "=", &sp); // x = NULL
+ // s = "abc\0-def\0"
+
+ Caveat: It modifies the original string.
+ Caveat: These functions cannot be used on constant strings.
+ Caveat: The identity of the delimiting character is lost.
+
+ See also mbssep(). */
+extern char * mbstok_r (char *string, const char *delim, char **save_ptr);
+#endif
+