build: create compile_commands.json
build: create compile_commands.json

Run tools/make-compile-commands on build, and re-run it in response to
Makefile changes.

We might also consider to create this as a result of running
./configure, but let's keep this simple for now.

mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit