pgsql: - Add Fortuna PRNG to pgcrypto.

Log Message:
-----------
- Add Fortuna PRNG to pgcrypto.
- Move openssl random provider to openssl.c and builtin provider
to internal.c
- Make px_random_bytes use Fortuna, instead of giving error.
- Retarget random.c to aquiring system randomness, for initial seeding
of Fortuna. There is ATM 2 functions for Windows,
reader from /dev/urandom and the regular time()/getpid() silliness.

Marko Kreen

Modified Files:
--------------
pgsql/contrib/pgcrypto:
Makefile (r1.18 -> r1.19)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgcrypto/Makefile.diff?r1=1.18&r2=1.19)
internal.c (r1.17 -> r1.18)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgcrypto/internal.c.diff?r1=1.17&r2=1.18)
openssl.c (r1.20 -> r1.21)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgcrypto/openssl.c.diff?r1=1.20&r2=1.21)
px.h (r1.12 -> r1.13)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgcrypto/px.h.diff?r1=1.12&r2=1.13)
random.c (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgcrypto/random.c.diff?r1=1.10&r2=1.11)