The RAND_DRBG API was added in PR #5462 and modified by PR #5547.
This commit adds the corresponding documention.
Reviewed-by: NKurt Roeckx <kurt@roeckx.be>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5461)

Apparently applications rely on RAND_load_file's ability to work with
non-regular files, customarily with /dev/urandom, so that the ban was
not exactly appropriate.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NBernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
Reviewed-by: NTim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5737)

Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4537)

Add a new config param to specify how the CSPRNG should be seeded.
Illegal values or nonsensical combinations (e.g., anything other
than "os" on VMS or HP VOS etc) result in build failures.
Add RDSEED support.
Add RDTSC but leave it disabled for now pending more investigation.

Refactor and reorganization all seeding files (rand_unix/win/vms) so
that they are simpler.

Only require 128 bits of seeding material.

Many document improvements, including why to not use RAND_add() and the
limitations around using load_file/write_file.
Document RAND_poll().

Cleanup Windows RAND_poll and return correct status

More completely initialize the default DRBG.
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3965)

Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3938)

Reviewed-by: NTim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3883)

Document an internal assumption that these are only for use with files,
and return an error if not. That made the code much simpler.
Leave it as writing 1024 bytes, even though we don't need more than 256
from a security perspective.  But the amount isn't specified, now, so we
can change it later if we want.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3864)

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1900)

Move manpages to manX directories
Add Windows/VMS install fix from Richard Levitte
Update README
Fix typo's
Remove some duplicates
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NAndy Polyakov <appro@openssl.org>

Previously we would try %RANDFILE%, then %HOME% and finally "C:".
Unfortunately this often ends up being "C:" which the user may not
have write permission for.

Now we try %RANDFILE% first, and then the same set of environment vars
as GetTempFile() uses, i.e. %TMP%, then %TEMP%, %USERPROFILE% and
%SYSTEMROOT%. If all else fails we fall back to %HOME% and only then "C:".
Reviewed-by: NRich Salz <rsalz@openssl.org>

Fix some code examples, trailing whitespace
Fix TBA sections in verify, remove others.
Remove empty sections
Use Mixed Case not ALL CAPS in head2
Enhance doc-nits script.
Remove extra =cut line
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NKurt Roeckx <kurt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

If something was "present in all versions" of SSLeay, or if it was
added to a version of SSLeay (and therefore predates OpenSSL),
remove mention of it.  Documentation history now starts with OpenSSL.

Remove mention of all history before OpenSSL 0.9.8, inclusive.

Remove all AUTHOR sections.
Reviewed-by: NTim Hudson <tjh@openssl.org>

L<foo|foo> is sub-optimal  If the xref is the same as the title,
which is what we do, then you only need L<foo>.  This fixes all
1457 occurrences in 349 files.  Approximately.  (And pod used to
need both.)
Reviewed-by: NRichard Levitte <levitte@openssl.org>

"make update".

pages into one for improved readability, add lhash manpage

Clean up bn_mont.c.

this is what we now use to read $RANDFILE / $HOME/.rnd.
(Previously, after 'cat'ting lots of stuff into .rnd
only the first MB would be looked at.)

Bugfix for apps/enc.c: Continue if RAND_pseudo_bytes returns 0
(only -1 is an error).