Add ccls compile_commands.json auto-generation support
For those in this world that use a LSP and
ccls along with tor code base, this ticket is about adding a
make lsp command that would use
bear to generate the
compile_commands.json to the root of tor.git.
Next step will be to add a proper
.ccls file defining all the
-D*_PRIVATE that we have in order to access those symbols.