Gcc < 3 does not consider regparm declarations for function pointers.
This causes big trouble at least with pollers (and with any function
pointer after all). Disable CONFIG_HAP_USE_REGPARM for gcc < 3.
Some of the tv_* functions are called very often. Passing their
arguments as registers is quite faster. This can be disabled
by setting CONFIG_HAP_DISABLE_REGPARM.