#11 ruby-gtk2: win32 vc10: cl /I option

[hATrayflood]

I tried to build ruby-gtk2 with ruby-1.9.2 http://www.artonx.org/data/asr/ and GTK+win32 http://www.gtk.org/download/win32.php .

1.
some extconf.rb checks -I option. but cl accepts both -I and /I option. and CFLAGS in .pc(GTK+win32) is /I style.
extconf.rb needs to checks -I and /I.

2.
gobject-2.0.pc has not CFLAGS. but extconf.rb checks gobject-2.0.pc for gsignal.h.
if CFLAGS in gobject-2.0.pc is blank, extconf.rb needs to use CFLAGS in glib-2.0.pc instead of gobject-2.0.pc.

[hATrayflood]