oi-build needs check-environment target
The oi-build framework needs a "check-environment" top level target which will sanity check the build host.
This could have negative checks in addition to positive ones (eg: check for X, if present warn it should not be - rather than just checking for things that should be present. Like environment variables that may affect a build).
The initial suggested list of checks are:
1. Check OS version (eg: oi_151 or newer)
2. Check for prerequisite Sun Studio versions
3. Check for package list on http://wiki.openindiana.org/oi/Building+Userland
4. Check for new enough pkg5 version