s/off_t/size_t

Reported by:	antoine
More s/off_t/size_t/g

Conflicts:
	libpkg/pkg_jobs_universe.c
Initialize use_ipvx
Use the right variable
Fix failures with gcc 4.2
Fix warnings spotted by clang 3.5
Appease yet more gcc 4.2
Actually align everything on off_t is a better idea
More gcc 4.2 warning fixes
gcc 4.2 is really dumb
Uselessly initialize path to please gcc 4.2