On Sun, 14 Feb 2016, Kyle Auble wrote: [...]
It's been several months so I could be completely misremembering, but I want to say ccache didn't seem to help even subsequent builds of wine on my system (which has really old hardware). Just keeping the object files for make (which is a no-go for final tests) seemed to make a much bigger difference.
Not sure why keeping the object files would be a no-go (at least for preprocessor mode).
However, note that nowadays ccache has two modes: * 'Preprocessor mode' where where ccache runs the preprocessor on the source code and hashes the result to find the object file in its cache.
* 'Direct mode' where ccache hashes the source code and include files directly which lets it skip the preprocessor step too. There's a catch in this mode which is that creating a new header file may change the code that would be compiled, without ccache detecting it.
Direct mode should improve compilation times at least as much as precompiled headers.