Try to split off the mingw portions of the libevent diff so we can send them to niels separately. Adding two patches: one that applies against 1.1b; one that applies against the libevent svn trunk.
svn:r8383
- made configure link to required system dll's if building for win32
- added diffs for libevent 1.1b
- forced user to turn off eventdns if win32 is set
- cleaned up tor_mmap_file()_win32 (not sure if it's stable)
- cleaned up some warnings and typos
svn:r8322
