Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

o style.Makefile(5): WARNS= -> WARNS?=.

Small regression test tool to generate two forms of ENOSPC on a file
system: out of blocks, and out of inodes. Useful for exercising the
uprintf(9) calls in UFS/ext2fs in order to detect races.