Fix mpy-cross build on Apple M1 machines

[djix123]

Patch to fix build of mpy-cross on Apple M1 machine

(Fix is a direct copy from latest micropython/py/nlraarch64.c)

[dhalbert]

@djix123 I tested #4832 on an M1 and did not get an error. I'm not doubting this is necessary, but what problem did you run into?

[djix123]

Using 'gcc-arm-none-eabi-10-2020-q4-major' I get:

Use make V=1, make V=2 or set BUILD_VERBOSE similarly in your environment to increase build verbosity.
QSTR updated
Undefined symbols for architecture arm64:
"_nlr_push", referenced from:
_mp_iternext in runtime.o
_mp_load_method_protected in runtime.o
_mp_parse_compile_execute in runtime.o
_it_iternext in objgetitemiter.o
_mp_execute_bytecode in vm.o
main in main.o
(maybe you meant: _nlr_push_tail)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mpy-cross] Error 1

when executing: make -C mpy-cross.

Looks like some kind of function name generation difference, since all the patch does is add the leading '_'.

[dhalbert]

@jepler Do you know why we did not see the problem above when you added the M1 builds?

[jepler]

Yes, when built by the ci it used a different makefile which forced setjmp-based nlr. That will be unnecessary after this change.

[jepler]

thank you