TLC for C99 inline implementation

TLC for C99 inline implementation

there's no need for two new flags in type.t .  We just can't use
VT_EXTERN as marker if functions are defined or not (like we can
for objects), and then can simply implement the rules of C99/C11
by not overwriting VT_STATIC/VT_EXTERN at all but rather only
look at them.  A function already on the inline list can be
forced by removing the VT_INLINE flag, and then linkage
follows from some combination of VT_STATIC, VT_EXTERN and VT_INLINE.