What's not clear to me if it is possible to recover a private key that is
damaged this way? If you change expiration with 1.4, the self-signatures are
lost and some key flags are changed. Is it possible to recover from that? That
is the problem I'm concerned with -- if it isn't possible to recover, it seems
people end up with damaged secret subkeys after changing expiration date on a
subkey with gnupg 1.4/2.0.

my$ printf "what do ya want for nothing?" | ./hmac256 Jefe
hmac256: fatal error: self-test failed
my$

Out of curiosity, I tried to rebuild the 1350 revision that you linked to below,
and it also worked. I'm not sure what happened, but at least I cannot reproduce
this any more.

I've re-run the 'basic' self test several time, and it works every time (except
for the hmac problem).

I'm relatively certain that it is correct. I created by running 'make dist' on
my machine and transferring the entire libgcrypt-*.tar.gz archive to the Solaris
system and building libgpg-error and the libgcrypt archive there. The system
doesn't have libgpg-error or libgcrypt installed before. The only way I see
them being wrong would be if there is a gdb/gcc problem, which isn't completely
unlikely, the tools on that platform are fairly old (gcc 3.4.4).

It doesn't seem to work:

If you make a release candidate I can test it on a solaris machine.