Remove documentation of BN_zero_ex() and update BN_one() and BN_zero()
which are no longer macros (and the latter is no longer deprecated and
no longer attempts to allocate memory).

mention what BN_ULONG is

document BN_zero_ex(3)

Add missing const qualifiers in a number of BN_* manuals.

ok schwarze

found a complete archive of SSLeay-0.4 to SSLeay-0.8.1b tarballs
on the web, so fix up SSLeay HISTORY accordingly

bn.h HISTORY up to SSLeay 0.8.1b; researched from OpenSSL git

Correctly describe BN_get_word(3) and BN_set_word(3).
These functions constitute an obvious portability nightmare,
but that's no excuse for incorrect documentation.

Pointed out by Nicolas Schodet
vi

Correctly describe BN_get_word(3) and BN_set_word(3).
These functions constitute an obvious portability nightmare,
but that's no excuse for incorrect documentation.

Pointed out by Nicolas Schodet
via OpenSSL commit b713c4ff Jan 22 14:41:09 2018 -0500.

show more ...

replace all references to bn(3) with BN_new(3),
and make sure all BN*(3) pages point back to BN_new(3)

Copyright and license

some cleanup;

first pass; ok schwarze

document BN_set_negative() and BN_is_negative();
feedback and OK bcook@, OK jsing@

fourth batch of perlpod(1) to mdoc(7) conversion