[Dovecot] Checking for strtoumax and strtoimax

[J Springer]

Tru64 5.1b PK6 : dovecot 1.1.7 : cc

Configuration checks for strtoumax and strtoimax are positive but both are
unresolved during compilation. strtoq and strtouq checks are negative.

I can modify compat.c to use "unsigned long ret = 0;" in place of strtoumax 
(does this break anything?) and/but I would like to know how to handle strtoimax.

Thanks in advance.