Comment 3 for bug 1553304

> What other variables do you think we might need?

Basically everything known to the build system would be of use to some target applications (excepting rtems/vxworks). And, again excepting rtems/vxworks the cost of doing so is negligible.

1. I'd like to get the Base version number components in numeric form (as in epicsVersion.h). No sense in having to parse this out.

2. CMPLR_CLASS and OS_CLASS for the same reason as T_A (or whatever you want to call it)

3. CROSS_COMPILER_TARGET_ARCHS and everything which goes into the pkg-config files. This would be helpful to downstream apps., particularly interpreters, using different build systems. Something along the same lines as https://docs.python.org/2.7/library/sysconfig.html