crypto/openssl: fix importing new versions from pristine trees

Prior to this change, CC was not being passed through to Configure,
which was resulting in failures when Configure was running compiler
checks.

Pass through CC via WRK_ENV to Configure so the compiler is defined
properly as part of the initial build.

MFC after: 1 month
Fixes: d18058b7b850 ("crypto/openssl: apply polish to new vendor import process")
Differential Revision: https://reviews.freebsd.org/D52595