pkg-config meta-files on install (*.pc) would simplify linking Surelog/UHDM in other projects

[hzeller]

For easier reference in other build systems (that are not cmake), it would be good to have pkg-config compatible files. Currently only *.cmake files are generated that only work with that specific build system, while pkg-config is the universal tool usually used in other contexts.

That way e.g. the Yosys plug-in wouldn't need the cumbersome setting of the UHDM_INSTALL_DIR but could figure it out by calling e.g. pkg-config --cflags uhdm and pkg-config --cflags surelog.