7. ICU required RTTI - WebKit porting to Mona OS

While porting ICU, I found ICU requires C++ rtti. I met a library for the first time which requires C++ rtti. Sigh.
Since our OS doesn't support C++ rtti and exceptions, we have two options.

Although it seems the latter options is easy, choosed the formar one. I think it's good time to build cross compiler with libsupc++ which implements rtti and exceptions.