Reinstate double-link generation of dynamic libraries.

Simplify slightly.
Use with Python 2.3 frameworks mostly working.


[SVN r16026]

tools/build

@@ -1 +1 @@
-Subproject commit 0691657f510d2dbad2a6b01a34b2497bb3e267e3
+Subproject commit 7b47ebce7dd48ce9c7f4c907d2b013c5371122a6