[Interest] Building 32-bit Qt 5 on Mac

[Stephen Chu]

So I grabbed Qt 5 from git to give it a shot again. I am now more 
confused then before. :)

The configure script uses pre-processor output from 
qtbase/config.tets/arch/arch.cpp to determine the host and target 
architectures (around line 3707). I assume this is to setup compiler 
flags for various features (SSE2, etc).

It then check the architecture that qmake is built in and adds it to 
QT_CONFIG (line 4968). This makes the built libs in the same 
architecture as qmake.

I guess I need to make/hack/trick the 2 the same to have a chance to 
make it work? The former is using i386 while the later wants x86. So I 
can't just copy them.

I don't think I am capable of coming up with a elegant solution. The 
only way I can do it is to just hard code the architectures into the 
configure script and hope for the best. :(