strsep - extract token from string
char *strsep(char **stringp, const char *delim));
The strsep() function returns the next token from the string
stringp which is delimited by delim. The token is ter-
minated with a `\0' character and stringp is updated to
point past the token.
The strsep() function returns a pointer to the token, or
NULL if delim is not found in stringp.
The strsep() function was introduced as a replacement for
strtok(), since the latter cannot handle empty fields.
(However, strtok() conforms to ANSI-C and hence is more
index(3), memchr(3), rindex(3), strpbrk(3), strspn(3),