Finally I successfully built C::B in MacOSX10.8 and wxWidget2.8 , got an "i386" app.
Not sure whether it works all correctly, but it does run

the patch is attached, including some wx2.9 refacting (but not complete)
steps:
1. download Xcode4.2.1 and extract MacOSX10.6 SDK to /Developer manually by 'tar -xvf xxxxxx'
2. build wxWidget 2.8
#!/bin/sh
arch_flags="-arch i386"
../configure CFLAGS="$arch_flags" CXXFLAGS="$arch_flags" CPPFLAGS="$arch_flags" LDFLAGS="$arch_flags" OBJCFLAGS="$arch_flags" OBJCXXFLAGS="$arch_flags" \
--disable-shared --enable-unicode \
--prefix="$(pwd)" \
--with-libjpeg=builtin \
--with-libpng=builtin \
--with-regex=builtin \
--with-libtiff=builtin \
--with-zlib=builtin \
--with-expat=builtin \
--with-macosx-sdk=/Developer/SDKs/MacOSX10.6.sdk --with-macosx-version-min=10.6
3. build C::B with all plugins
apply the patch first. I hope the patch can be merged into trunk
you may need to install some third party packages like 'hunspell'
the 'brew install hunspell' only gets a x86_64 version,
so I used 'brew install --interactive hunspell' and modifid Makefiles to get a universal libhunspell
arch_flags="-arch i386"
./configure --with-wx-config=/usr/local/bin/wx-config-2.8 --with-contrib-plugins=all \
CFLAGS="$arch_flags -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-version-min=10.6" \
CXXFLAGS="$arch_flags -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-version-min=10.6" \
CPPFLAGS="$arch_flags -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-version-min=10.6" \
LDFLAGS="$arch_flags" OBJCFLAGS="$arch_flags" OBJCXXFLAGS="$arch_flags"
the bundle refers Step 3 in
http://forums.codeblocks.org/index.php?topic=15108.0