This can be used with a clangd server to get code completion and cross
references in editor. To simplify the generation, create .cmd files for
most object files while building that contains the base directory and
command that was used when compiling it.
A very simple gen_compile_commands.py is provided which will read one or
more build directories and generate the compile_commands.json file for
it.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>