[OpenBIOS] Allow building on Mac OS X

[Programmingkid]

> On Apr 13, 2015, at 3:58 PM, BALATON Zoltan wrote:
> 
> Hello,
Good to hear from you again. It has been a while. Hopefully you haven't given up on making MorphOS boot in QEMU.

> I've seen your patches on the OpenBIOS mailing list, here are some comments.
> 
> * instead on disabling -Werror completely you may want to try -fno-strict-aliasing (and if possible only set it for the file which exhibits this problem but I'm not sure how to do that with the used build system). The usb driver came from coreboot and probably had this problem there already but I did not see these warnings. It may be a peculiarity of your compiler or build environment.

There are differences between Apple's supplied gcc and what Linux users usually use. That could be the reason for the errors on Mac OS X. If it is possible to set that option for the problem file, I will try to do so. Disabling Werror doesn't seem like such a big deal. Without it I can see the warning messages and still continue compiling ... a win-win situation. 

> * At least on OS X 10.9 /bin/sh is the same as /bin/bash and /usr/bin/uname -m returns x86_64 (the same as I get on Linux) so these changes should not be needed. (I did not check on older versions though.)

The change from sh to bash was not to accommodate Mac OS X, it was to fix a problem on Linux. This code "filtered_list=${filtered_list:0:$end}" would fail on Debian Linux when the sh shell was set. I read on stackoverflow.com that Linux usually has sh set to Dash instead of bash. The switch in shells didn't cause anymore problems, so it seems good. 

> Are you running a 32 bit OS and compile for 64-bit target on that?
Not doing that. Here is the output of uname -a:
Linux debian 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012 x86_64 GNU/Linux

> Or do you have another version of these commands in your path overriding the system provided ones?
I'm not aware of anything like this happening.

Thank you for reviewing my patch.