I had another issue show up with building dahdi-linux. I get an error message:
FATAL: modpost: GPL-incompatible module dahdi_vpmadt032_loader.ko uses GPL-only symbol
'debug_lockdep_rcu_enabled'
Looking around I saw a suggestion that this was triggered by configuring
CONFIG_LOCKDEP which results in third party modules picking up GPL only
sysmbols.
Is this likely to change soon, or do I need to handle this on my end?