GitLab

Adds simple jobs for building the library for Debian 10.

Pre-built docker images containing Sequoia will be pulled down and u

Pre-build odcker images containing Sequoia will be pulled down and used
to build the Engine. Currently the Sequoia version is just the latest
from the `pep-engine` branch. We should make this selectable in the near
future.

Upon successful compilation an image containing the build output will be
pushed to an internal docker registry.

Merge branch 'ENGINE-864'. This merges in some generic Makefile refactoring as well as the changes so that pEpMIME can be built in to the engine (this requires a separately checked-out pEpMIME repo, setting PEP_MIME to 1 in the local.conf file, and ensuring PEP_MIME_SRC is set properly. System also needs boost to do built-in parsing, but if you don't touch the PEP_MIME variable, we still default to etpan. Please contact krista with a copy of your local.conf and the compiler error if you can't get it working. (Does not apply to non-MacOS/*nix-flavoured OSs for the time being...)

ENGINE-864: Cleanup, plus fixed some semantics regarding CFLAGS/CXXFLAGS/CPPFLAGS that had been built in to the build system.

ENGINE-864: Shut off PEP_MIME default (use PEP_MIME=1 in local.conf to activate for testing fun) - only tested on MacOS so far. Next stop: debian.

Kludged Makefiles that actually work with pEpMIME (with a modified branch), but aren't yet what we want. Was just to get it to run.

ENGINE-824: ENGINIE-825: flags for group identities and organisational (i.e. business vs. private) identities

ENGINE-800: semantics for stringlist_append are now that if the second pointer is sequal to the first, we copy the list and append it. This matches the copy semantics of other-pointer appends.