The I-guess relevant portion of the output of perl -V is
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef usemultipl
+icity=undef
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
on the 64-bit machine. I'll edit this comment from my 32-bit machine in a few minutes.
UPDATE: Here's the same passage from my 32-bit machine:
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef usemultipl
+icity=undef
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
but maybe it's this bit that's more interesting:
Compile-time options: PERL_MALLOC_WRAP USE_FAST_STDIO USE_LARGE_FILE
+S
USE_PERLIO