Back again, after a major hard drive failure taught me an important lesson about making backups...
Before updating zlib to the latest version, I wanted to build from source, with tuning optimisations enabled.
Optimising zlib was achieved editing make_vms.com
-- ccopt3 = '/opt=(inline'
++ ccopt3='/opt=(tune=host,inline=speed)
Installation of the updated images required renaming of two files prior to running install_libz_gnv.com
libzshr.exe to gnv$libzshr.exe
gnv_zlib_startup.com to gnv$zlib_startup.com
Then run install_libz_gnv.com to copy the files into the right GNV directories.
