Building DKMS module with macro in Makefile

[Sepi Gair <sepigair@email.cz>]

Hello,

I'm trying to package the DKMS module which passes the macro within 
Makefile. Specifically, Makefile defines `SOME_VAR:=SOME_VALUE` and uses 
make variable to pass macro as follows: 
`CFLAGS_MODULE='-DSOME_VAR=\"$(SOME_VAR)\"'`. As a result, this 
construction ignored on install so the building of the module produces 
the error: `error: expected ‘)’ before ‘SOME_VAR’`.

I wrote simple package to make it easy to reproduce my issue: 
https://salsa.debian.org/spg/dkmsfail.

Is it possible to package this module without patching source code? 
Which documentation should I read to learn building flow?

Thank you.