Clean up the addition of inflateGetDictionary.
Clean up the addition of gzvprintf.
Add casts and consts to ease user conversion to C++.

You would still need to run zlib2ansi on all of the *.c files.
Add man pages for minizip and miniunzip.
Minor spacing cleanup in a comment in gzguts.h.
In Makefile uninstall, don't rm if preceding cd fails.
Do not return Z_BUF_ERROR if deflateParam() has nothing to write.

If the compressed data was already at a block boundary, then
deflateParam() would report Z_BUF_ERROR, because there was nothing
to write.  With this patch, Z_OK is returned in that case.