config.hh: eliminate its uses
We should no longer depend on config.h to find our files. That's one of the motivations for config.yaml. Currently, if we pass a new --prefix
, we recompile almost all the platform. It does not make sense.
Maybe we should also stop maintaining the C++ code for C++ compilation, and support only vcsn compile
. But at least if we keep the C++ code, it must use config.yaml.