Fix for bug 2283 (RVCT 4.0 support is missing from PDK 3.0.h)
Have multiple extension sections in the bld.inf, one for each version
of the compiler. The RVCT version building the tools will build the
runtime libraries for its version, but make sure we extract all the other
versions from zip archives. Also add the archive for RVCT4.
EXPORTS
Init9 @ 1 NONAME
ChkC9 @ 2 NONAME
BlkI9 @ 3 NONAME
GetGeneration @ 4 NONAME
RBlkI9 @ 5 NONAME
SetCloseLib @ 6 NONAME