Mutations of the environment can invalidate pointers to environment
variables, so make `secure_getenv()` copy them out instead of returning
pointers.

PR-URL: nodejs#11051
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Move some code around so we can properly test whether the switch
actually does anything.

PR-URL: nodejs#11255
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Commit a8734af ("src: make copies of startup environment variables")
from two weeks ago introduced a regression in the capturing of the
`--icu-data-dir=` switch: it captured the string up to the `=` instead
of what comes after it.

PR-URL: nodejs#11255
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Allow it to be used anywhere in src/ that env variables with security
implications are accessed.

PR-URL: nodejs#11006
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

A side-effect of https://github.com/nodejs/node-private/pull/82
was to remove support for OPENSSL_CONF, as well as removing the default
read of a configuration file on startup.

Partly revert this, allowing OPENSSL_CONF to be used to specify a
configuration file to read on startup, but do not read a file by
default.

If the --openssl-config command line option is provided, its value is
used, not the OPENSSL_CONF environment variable.

Fix: nodejs#10938
PR-URL: nodejs#11006
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>