Solution: establish a matrix of CI options. On one axis we have the
build system (autotools, cmake, android) and on the other axis we
have the encryption options (tweetnacl, libsodium or none).
- they have no copyright / license statement
- they are in some randomish directory structure
- they are a mix of postable and non-portable files
- they do not conform to conditional compile environment
Overall, it makes it rather more work than needed, in build scripts.
Solution: clean up tweetnacl sauce.
- merged code into single tweetnacl.c and .h
- standard copyright header, DJB to AUTHORS
- moved into src/ along with all other source files
- all system and conditional compilation hidden in these files
- thus, they can be compiled and packaged in all cases
- ZMQ_USE_TWEETNACL is set when we're using built-in tweetnacl
- HAVE_LIBSODIUM is set when we're using external libsodium
The decision about the poller mechanism to use (select, poll, ...)
was done twice: once by the build system and once by the code in
poller.hpp. As the build-system can actually detect the mechanisms
available, prefer that result to the hard coded defaults in
poller.hpp.
At the same time, remove the duplicate detection of select() vs.
poll()-variant from proxy.cpp, signaler.cpp and zmq.cpp.
This patch has not been tested on many build platforms: especially
the cmake build needs testing / patching. For the other builds,
hard code the result as these these are all Windows platforms.
