Added a buildroot archive step to save the current build environments.
Try to infer the build and runtime configuration if environment variables aren't set.
Add include and library paths to the end of the compiler command line so they don't override normal command line parameters.
Don't include the full path in the patch checksum in case the build directory is moved.
Don't include the libc development package since it conflicts with the cross-compiler libc support.
Added additional packages useful for building games in the Steam runtime.