This commit re-writes Borland compiler build rules.  We split the rules
into modern <os>-<id>-<lang> information modules but share a common
macro between languages to avoid duplication.

We also address a bug in the previous rules that would build some target
types against the static Borland runtime and others against the shared
Borland runtime in one build tree.  Now we always use the shared runtime
as is the default in the rules for MS tools.