Implement os_find_datadir for OS X

OS X has an _NSGetExecutablePath interface for obtaining the
path of the currently executing binary. This can be used
to implement os_find_datadir.
configure: Detect --disable-system and --target-list conflicts.

The user should not be allowed to configure a softmmu target
when --disable-system is selected.

Signed-off-by: Ben Leslie <benno@benno.id.au>
Remove unnecessary #include of console.h

console.h is unnecessarily included in some .c files, remove
it to reduce dependencies.
Provide --disable-console option

It is not always desirable to compile Qemu with a graphical
console. --disable-console disables the Qemu console.

This has a relatively large impact on machines and devices that
assume the existence of a graphical console. The option is only
useful if you are compiling a specific sub-set of machines that
don't use the graphical console.

Console currently includes input as well as output. This could
potentially be refactored to remove this dependency.
Print console configuration status
Conditionally compile ARM objects.

Currently, the ARM Makefile includes all available objects, with
not configuration possible to disable certain features, platforms,
machines, or drivers.

This adds configuration options so that a subset can be easily
compiled (by specifying in arm-softmmu.mak)
Minimal ARM configuration.

The ARM configuration is modified to provide a minimal
configuration, that only supports Stellaris.
Disable stellaris OLED driver when console disabled.

The OLED driver requires console support.
Enable stellaris without a console disabled.

Stellaris use an input driver for simulating attached gamepads.
If the console is not enabled, skip registering the gamepad device.
block: Remove dead code.

Trivial clean-up that removes commented out code.
Fix vCont single-step reply when target has no ice

Currently vCont replies that single-step is supported, however
on targets without ICE it is not possible to single-step. This
makes the vCont reply packet conditional on the availability
of ICE.
Set ARM thumb enabled if bit zero of PC is set

When the program counter is set the current code masks out
the bottom bit. The general intention when setting the low
bit on a code address on ARM is to enable thumb mode, so
emulate this behaviour in the gdbstub. Ideally check if
a similar behaviour occurs on real hardware.
Initialise stack variable

Picked up by -Werror rc can be used unitialised. There may
be some global knowledge that ensures this case is not possible,
but from purely local reasoning it seems possible that rc may
be used before initialisation.
Make loading ROM to a bad address an error.

Currently if you try to load a ROM into a non-existent region
it is silently ignored. This changes such a case in to a hard
error instead. This ensures that if an ELF file with bad
addresses is loaded, the user knows about it, rather than
having to guess what the problem is.
Provide option to disable IDE.

On embedded targets there is no need to compile IDE support;
provide a mechanism for disabling.
Provide --disable-usb configuration option.

It is not always desirable to enable host USB support, so
provide an option to disable.
Added simple_armv7m machine.

Rather than any physical device, the simple_armv7m machine
is a simple machine that makes testing and debugging easier.