Fix the build enviroment to allow easy building as a Linux native application.

I suggest that this current 'linux' option be renamed to 'linux-iphone', which is for cross-building a iPhone application on a Linux machine.

Simon

Adds supports for a native linux build. You can specify this using the '--target=native' option for configure.

'--target' seems to be defaultly set to 'iphone' so these changes should not affect other users.

and the makefile needs adjustment

hi simon. without --target, it should build for native (and it does on mac as far as I remember). I just didn't check someone else's patch to fix --target=iphone compilation on linux.

hi simon. I cleaned up the build that a plain configure && make will work on Ubuntu 10.10 (and all others too). I didn't have chance to test it, but it compiles at least. Could you give it a quick try?