opt: functions to show integer values with kMGTPE suffixes
As with the set_ functions, there are twelve permutations of integer size,
base, and signedness. The supported sizes are int, long, and long long.
For example, this:
char buf1[OPT_SHOW_LEN];
char buf2[OPT_SHOW_LEN];
unsigned i =
1024000;
opt_show_uintval_bi(buf1, &i);
opt_show_uintval_si(buf2, &i);
will put "1000k" in buf1, and "1024k" in buf2.
Unlike the opt_set_ functions, these use unsigned arithmetic for unsigned values.
(32 bit bug using sizeof(suffixes) instead of strlen(suffixes) fixed by Rusty)