NetBSD doesn't provide AI_ALL for getaddrinfo(3).
Since NetBSD doesn't officially support gethostby{name,addr}_r(3),
make the configure not to pick up them (like other get..._r functions).
Even though the libc exports those symbols, no header file provides
prototypes for them.
NetBSD/{i386,amd64} 6.99.26 changed to use the x87 default control
word (0x037f) as initial value for new processes.  This means
floating point calculation is done in extended precision rather than
double precision on i386.  So, make sure that the double precision
is used where required.  The function fpsetprec(3) itself is introduced
in NetBSD 6.
Merge pull request #33 from enami/issue-1

Fixes some test failure on NetBSD/i386-curent