Building a cross compile of binutils on OS X Yosem

I'm trying to build binutils for generating MIPS code on Mac OS X.

I found this site (http://www.theairportwiki.com/index.php/Building_a_cross_compile_of_GCC_for_MIPS_on_OS_X) from How to build GCC 4.8.x on Mac OS X host for MIPS target, and followed the instructions.

I install the gcc-4.8 from brew, and installed source code of binutils and gcc. This is the compilation option setup.

$ export CC=/usr/local/bin/gcc-4.8
$ export CXX=/usr/local/bin/g++-4.8
$ export CPP=/usr/local/bin/cpp-4.8
$ export LD=/usr/local/bin/gcc-4.8
$ export PREFIX=/opt/cross/gcc-mips
$ export CFLAGS=-Wno-error=deprecated-declarations

Then I configure, and make the bintuils.

The issue is that after building static libraries I have an error message that archive is not built for x86_64, and then I have a bunch of undefined symbol error.

ignoring file ./../intl/libintl.a, file was built for archive which is not the architecture being linked (x86_64): ./../intl/libintl.a

Undefined symbols for architecture x86_64:
  "__bfd_abort", referenced from:
      _fix_new_internal in write.o
      _size_seg in write.o

Googling to find that I need to setup AR (archive) variable also from https://github.com/tpoechtrager/osxcross/issues/11. I added export AR=/usr/local/bin/gcc-ar-4.8, but I have another error message because gcc-ar-4.8 doesn't work.

/usr/local/bin/gcc-ar-4.8 
/usr/local/bin/gcc-ar-4.8: Cannot find plugin 'liblto_plugin.so'

Googling again to find that gcc-ar doesn't work with Mac OS X (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56893).

gcc-ar is for use with newer GNU binutils only as that is the only ar which supports plugins.  
Apple's ar does not support plugins (though it could be made to; it will be a different plugin interface than the GNU BFD 
plugin interface which GCC supports right now).

I just created a dumb 'liblto_plugin.so' file in /usr/local/Cellar/gcc48/4.8.4/libexec/gcc/x86_64-apple-darwin14.3.0/4.8.4 directory to suppress the error message, but in this case it looks like that /usr/ar is invoked when I use /usr/bin/gcc-ar-4.8 to get the same architecture and undefined symbols error.

How to solve these issues? How to build cross compiler tools (gcc and binutils) on Mac OS X?

The static library generator for Mac OS X is not ar, but libtool -static. There is another SO post about this - Static library link issue with Mac OS X: symbol(s) not found for architecture x86_64.

The binutils has multiple libraries that are linked statically. So I replaced all the ar rc command with libtool -static -o to get the static libraries that do not cause errors.

In doing so, I had to make two modifications also.

Some library generate libtool script to conflict the Mac OS X's libtool, I had to rename the script.
Some object files do not contain symbols, I had to remove the objects.

Then I could get the binaries without any issue.