aliases_of(): New method

Added AC_CHECK_SIZEOF(void *).
Added yet another test for pthreads (pthread_create may be in libc).
Added pthread_init to list of functions whose existence is checked.

<cdtv@amigager.de>.

"non-default argument follows default argument".

instead of silently supplying a default of None fore c.

expecting some contributions).

(Also removed whitespace after # in some BEOS related cpp directives.)

strings.  Reported by Lorenzo M. Catucci <lorenzo@argon.roma2.infn.it>.

Reported by Lorenzo M. Catucci <lorenzo@argon.roma2.infn.it>.

M. Catucci <lorenzo@argon.roma2.infn.it>).

*beyond* the null byte at the end of the input string, when the input
is inf(inity).  Discovered by Greg Ward.

here; pystate.h doesn't use it (I thought I wanted to move the array
there but that won't work).

pystate.h; pystate.h doesn't use it (I thought I wanted to move the
array there but that won't work).