Missing sysclib exports

[uyjulian]

I notice you are missing some sysclib exports. Here are some compared to the header files of ps2sdk:

 9 get_ctype_table (non-std)
10 memchr
15 bcmp
18 prnt (non-std)
26 rindex
28 strncat
31 strpbrk
33 strspn
37 atob (non-std)
38 strtoul
43 strtok_r

[jpd002]

Thanks for the list!

I implement the missing functions when a game needs it. I haven't come across any game that required these yet, but I can add them if you need them.