Dan Liew 2cb4223979 [CMake] Support including Git hash and description into the build. ... CMake will automatically pick up changes in git's HEAD so that the necessary code is rebuilt when the build system is invoked. Two new options `INCLUDE_GIT_HASH` and `INCLUDE_GIT_DESCRIBE` have been added that enable/disable including the git hash and the output of `git describe` respectively. By default if the source tree is a git repository both options are on, otherwise they are false by default. To support the `Z3GITHASH` macro a different implementation is used from the old build system. In that build system the define is passed on the command line. This would not work well for CMake because CMake conservatively (and correctly) rebuilds *everything* if the flags given to the compiler change. This would result in the entire project being rebuilt everytime git's `HEAD` changed. Instead in this implementation a CMake specific version of `version.h.in` (named `version.h.cmake.in`) is added that uses the `#cmakedefine` feature of CMake's `configure_file()` command to define `Z3GITHASH` if it is available and not define it otherwise. This way only object files that depend on `version.h` get re-built rather than the whole project. It is unfortunate that the build systems now have different `version.h` file templates. However they are very simple and I don't want to modify how templates are handled in the python/Makefile build system.		2017-03-12 22:11:59 +00:00
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cmake	[CMake] Support including Git hash and description into the build.	2017-03-12 22:11:59 +00:00