GCC 3 and above do not inline large functions, which is a problem
with ebtree where most core functions are inlined.
This simple patch has both reduced code size and increased speed.
It should be back-ported to ebtree.
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.
