crypto/openssl: apply polish to new vendor import process

[ngie]

Summary

This change does the following 2 things:

• Makes the build more repeatable by isolating the environment. This prevents bmake from leaking variables into gmake and makes the overall process a bit more robust.
• Add debug printouts to make the process more straightforward to the reader and whoever is executing doing the current vendor import.

MFC after: 1 month

[sjg]

crypto/openssl/BSDmakefile

29

SETENV seems a bit misleading, ENV is a bit too generic, perhaps CLEAN_ENV perhaps?

46

Using GMAKE rather than bare gmake would be better.
Or ${GMAKE:Ugmake} if you don't want GMAKE?= gmake somewhere

51

excursions like this should be in () to avoid confusing other steps in jobs mode.
Ie. in jobs mode all commands in a target are fed to a signle shell instance, so the find below will behave differently in jobs mode vs compat mode

[ngie]

crypto/openssl/BSDmakefile

29

I was trying to follow the naming convention established by ports, but I probably should have used SETENVI: https://cgit.freebsd.org/ports/tree/Mk/bsd.commands.mk#n85 .

51

Interesting. Will adjust!

[ngie]

Address comments from @sjg.