Recompiling hpricot_scan.so

I am trying to make some changes to increase the buffer size in hpricot. I installed mingw and msys. When I run extconf.rb I get this error : checking for main() in c.lib... no creating Makefile

and then when I run the make file I get this: Makefile:127: *** target pattern contains no `%'. Stop.

What am I doing wrong?