It would seem that enabling GCC's type conversion/truncation warnings would be a good thing for Python builds.

This would bring GCC builds in line with MSVC builds and reduce the burden on the Windows developers in fixing them.  Also, it would bring attention to those issues by the developer who writes code and would hopefully understand the truncation issues at hand.

The CFLAGS required for this are '-Wconversion -Wno-sign-conversion'.

I unfortunately do not know the autoconf foo needed to implement this suggestion, however.  Perhaps it should only be enabled for debug builds as well to eliminate excess noise for other builds.  Or at least enabled on some of the buildbots.