script/build-with-container: add CONFIGURE_ARGS env var to configure step

script/build-with-container: add CONFIGURE_ARGS env var to configure step

Add a new optional CONFIGURE_ARGS environment variable to the configure
step so that there's a mechanism to pass custom cmake options that
aren't handled elsewhere in the run-make.sh script.

Because configure is a rather fundamental build step it's probably
preferable to set this via an env file so that it persists across
rebuilds. Using an environment var here also avoids both needing to
change run-make.sh or add another CLI option to BWC which already has
too many.

Signed-off-by: John Mulligan <jmulligan@redhat.com>