char * strstr_PF(const char *s1, uint_farptr_t s2)
The strstr_PF() function finds the first occurrence of the
substring s2 in the string
s1. The terminating '\0' characters are not compared.
The strstr_PF() function is similar to strstr() except that s2 is a far pointer to a
string in program space.
The strstr_PF() function returns a pointer to the beginning of
the substring, or NULL if the substring is not found. If
s2 points to a string of zero length, the
function returns s1. The contents of RAMPZ SFR are
undefined when the function returns