This code generates quite a few lint warnings - partially because of c9x
constructs, partially because of questionable code. Here's some examples:

/home/dogcow/work/nbobj/dd/usr/include/fs/puffs/puffs_msgif.h(396): warning: zero sized struct [47]
(c9x)

/home/dogcow/work/nbsrc/lib/libpuffs/subr.c(109): warning: conversion to 'unsigned int' due to prototype, arg #3 [259]
(unknown)

/home/dogcow/work/nbsrc/lib/libpuffs/subr.c(130): warning: comparison of unsigned int with negative constant, op != [162]
(bad.)

Also, subr.c bombs completely:
/home/dogcow/work/nbsrc/lib/libpuffs/subr.c: In function 'puffs_vtype2dt':
/home/dogcow/work/nbsrc/lib/libpuffs/subr.c:170: warning: comparison of unsigned expression < 0 is always false

I'm also a little unsure why vdmap/puffs_vtype2dt exists, since
it's more-or-less duplicating everything in the original vtype enum
to begin with.