Re-write t_agetstr() so that it does not use realloc so userland
programs don't break. We now use an internal buffer to keep track
of the memory we allocate. This changes the api of t_agetstr() to
take 2 fewer arguments, but there are not many programs that use it.
Please note that this does not change binary compatibility with the
previous t_agetstr() since the usage was:
char *area, *p;
*area = NULL;
t_agetstr(ti, "ic", &area, &p);
...
free(area);
Since we don't touch the arguments and free(NULL) is a no-op, nothing
breaks.
Since we don't break binary compatibility there is no reason to bump
the library's major number, but since we change t_agetstr() I'll bump
the minor number for good measure.
termcap entries simultaneously and lifts the 1024 byte limit on the termcap
entry. The original termcap api is unchanged but also no longer has
the 1024 byte limit if the termcap functions are used.
