Updates for omnibus-software for AIX

Compiler flags and updates to allow embedded software to be built on AIX with the XLC toolchain.
would this be a lot easier:

```
env['PATH'] = "/opt/freeware/bin:#{env['PATH']}" if aix?
```

then you don't clobber the with_embedded_path and with_standard_compiler_flags stuff.  and if there's something in there which makes the patch command unhappy, then it'd be better to clobber that out explicitly so its better documented rather than flushing all the standard omnibus env for an opaque reason.