move to cmake

[ra1nb0w]

Hello,
first of all thank for your effort!
I am trying to build direwolf on MacOS 10.14 and it fails and the build mechanism is not idempotent. What do you think if I re-write the build system in CMake and therefore have truly multi-platform support?

thanks

[wb2osz]

Adding new features to 3 different Makefiles (Linux, Windows, Mac OSX) is a maintenance headache. It would be nice to have a single build recipe to handle all platforms but I don't want to go down the autoconf road. Too complicated and too many bad experiences with it.

The Mac OSX case is the most problematic. I don't have a Mac, the build tools seem to keep changing and people tell me contradictory things.
The Linux Makefile, in the dev branch, already has a bunch of conditional stuff for FreeBSD and OpenBSD. I'm not happy with the current state.

I would consider cmake if:

(1) It is universally available everywhere (including FreeBSD, OpenBSD, Cygwin, etc.) using the standard package installation process (yum, apt-get, and so on). Users should not have to build cmake from source.

(2) The implementation handled all of the special cases such as different compiler options based on compiler version (e.g. is -fastmath available) and target hardware (e.g. -msse or -mfpu=neon which make a big difference in performance).

(3) It can handle situations where the same source is compiled multiple times with different conditional compilation depending on where it is used. For example, some library might have a main program which is used for unit test.

(4) Can handle other complications that might arise.

[ra1nb0w]

1. yes, cmake is becoming the standard; anyway debian prefer debian/ folder with debhelper or similar.
2. I wrote a multi-platform cpu flags discovery so we can use that (from sse2 to avx512 and neon)
3. yes
4. yes, and this is why 1

I will prepare a prototype (no deadline please) and we will discuss that.

[ra1nb0w]

Do you prefer that I use -dev or -master?

[wb2osz]

"dev" branch because that is where all development is happening.

[wb2osz]

This has been merged into the dev branch.
Feedback, from users of many different operating systems, has been positive.
Thanks for all the hard work you put into this.

[ra1nb0w]

thank you.

TODO:

• probably remove the inner folder created by cpack on the zip for windows
• rework deb/rpm packaging (ask to the respective maitainer)
• rewrite macOS build documentation. Now the procedure it is the same of GNU/Linux and to install dependencies you can use either macports or homebrew; for example
  sudo port install cmake portaudio [hamlib gpsd] then build direwolf as always.
  From 1.6 I will push direwolf to macports therefore the installation will be easier: sudo port install direwolf.