MingW and MiniDumps

Seems at least one mingw machine is missing the definitions for
minidumps. It does seem to have the header (dbghelp.h) that's
required, but with incomplete contents?

Can someone who has a working mingw environment look for the
definitions? See
http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=narwhal&dt=2010-12-19%2017%3A00%3A01
for ref on what's missing.

If they're not defined on mingw, I'm inclined to just not bother
building the crashdump functionality at all on mingw. It's likely less
useful there since mingw doesn't use windows compatible symbol tables,
but it might still be a bit useful due to our "export everything"
approach.

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/