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.
For a description of the files and programs in this directory, see the
"Base How To Use Automated USB Tests" document
\generic\base\documentation\Base_How_To_Use_Automated_USB_Test.doc.