windows: use '-l<library>' form in gyp file
windows: use '-l<library>' form in gyp file

This fixes the build with MinGW32.

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso