Initial Apple M1 support

[ThomasDebrunner]

This PR adds initial support native compilation on apple silicon (M1) macos.

Describe problem solved by this pull request
Apple is moving to their own arm64 based processor architecture. While at the moment one can run PX4 sitl perfectly fine in x86 emulation on those machines, having it running natively is more desirable.

Describe your solution
Two things are addressed:

• Submodule for jmavsim set to Native macOS ARM jogl binaries for M1 support jMAVSim#132. This version of jmavsim contains native OpenGL binaries for arm64, this makes it run on M1

• The gyro_fft module uses CMSIS. CMSIS has a lot of functions with inline arm 32-bit assembly. When compiling on x86 or any non-dsp and non-neon arm processor (such as the M1), none of these functions ever get used. This is what allows (presumably) to compile on x86. On M1, the story is the same. Also none of those functions ever get used, but since we are compiling to an arm target, the apple compiler somehow still issues warnings for the inline arm assembly using 32-bit registers instead of native 64-bit registers. Since we treat those warnings as errors, compilation fails. Disabling this specific warning on apple silicon fixes the issue. This seems to be an apple-clang thing. GCC on linux arm64 doesn't seem to have this issue.

Describe possible alternatives
It would be better if all those functions would be behind preprocessor statements to actually not be in the code for targets that do not support them, especially also x86. But since we just use CMSIS code, we should not alter those files

Test data / coverage
SITL runs in jmavsim, after installing the environment natively with homebrew from PX4/homebrew-px4#80

Additional context

To note:

• gazebo is not working yet
• When compiling for nuttx, we invoke the arm compiler binaries installed with the toolchain. Those compiler binaries are x86 and run therefore in rosetta. This is fine though and works out of the box.

Additional testing would be welcome!

[dlech]

I was able to get jmavsim to run using this. (this is all quite new too me, so don't think I can help with much more than just a compile test).

I did make some progress with fixing dylib errors like this on the gazebo build:

dyld[98448]: Library not loaded: @rpath/libgazebo.11.dylib
  Referenced from: /opt/homebrew/Cellar/gazebo11/11.9.0/bin/gzserver-11.9.0
  Reason: tried: '/usr/local/lib/libgazebo.11.dylib' (no such file), '/usr/lib/libgazebo.11.dylib' (no such file)

by running:

install_name_tool -add_rpath /opt/homebrew/lib /opt/homebrew/Cellar/gazebo11/11.9.0/bin/gzclient-11.9.0
install_name_tool -add_rpath /opt/homebrew/lib /opt/homebrew/Cellar/gazebo11/11.9.0/bin/gzserver-11.9.0

I'm still getting

dyld[1690]: symbol not found in flat namespace '_rmtMetal_usGetTime'

but google has 0 results for "_rmtMetal_usGetTime", so I'm not sure what that is.

[dlech]

but google has 0 results for "_rmtMetal_usGetTime", so I'm not sure what that is.

found something: Celtoys/Remotery#139

[dagar]

Merge the cmake change while you settle jmavsim?

[ThomasDebrunner]

@dagar Removed the jmavsim submodule update, just the cmake addition left. Ready for merge IMO

[dlech]

FYI, I got gazebo working with Homebrew/homebrew-core#90205 and osrf/homebrew-simulation#1698.

[ThomasDebrunner]

@dlech nice!