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

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

MFC r237410: zlib 1.2.7.

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

Approved by: re (implicit)

Set magic fbsd:nokeywords property that allows files to bypass
keyword expansion. (file-specific replacement for CVSROOT/exclude)

This commit was generated by cvs2svn to compensate for changes in r131377,
which included commits to RCS files with non-trunk default branches.

Import zlib 1.2.1 (trimmed)