tor/changes/ticket23845

  o Major features (embedding):
    - There is now a documented stable API for programs that need to
      embed Tor. See tor_api.h for full documentation and known bugs.
      Closes ticket 23684.

  o Code simplification and refactoring:
    - The tor_git_revision[] constant no longer needs to be redeclared
      by everything that links against the rest of Tor.  Done as part
      of ticket 23845, to simplify our external API.
Add a public tor_api.h with an implementation in tor_api.c The main effect of this change is to commit to an extensible long-term API. Closes ticket 23684. 2017-10-18 20:26:29 +02:00			`o Major features (embedding):`
			`- There is now a documented stable API for programs that need to`
			`embed Tor. See tor_api.h for full documentation and known bugs.`
			`Closes ticket 23684.`

Move tor_git_revision into a new module. At first, we put the tor_git_revision constant in tor_main.c, so that we wouldn't have to recompile config.o every time the git revision changed. But putting it there had unintended side effect of forcing every program that wanted to link libor.a (including test, test-slow, the fuzzers, the benchmarks, etc) to declare their own tor_git_revision instance. That's not very nice, especially since we want to start supporting others who want to link against Tor (see 23846). So, create a new git_revision.c file that only contains this constant, and remove the duplicated boilerplate from everywhere else. Part of implementing ticket 23845. 2017-10-18 19:49:35 +02:00			`o Code simplification and refactoring:`
			`- The tor_git_revision[] constant no longer needs to be redeclared`
			`by everything that links against the rest of Tor. Done as part`
			`of ticket 23845, to simplify our external API.`