I tried to build latest ARM compute library release version 21.11 on Apple silicon under mac os 11.1 and clang 12.0.0 by using command line from ACL document.
scons Werror=1 -j8 neon=1 opencl=0 os=macos arch=arm64-v8a build=native
But I got following build error:
src/cpu/CpuContext.cpp:31:10: fatal error: 'malloc.h' file not found
Is ACL code stable in Apple silicon?
It looks like you're hitting this error: https://github.com/ARM-software/ComputeLibrary/issues/925
It's fixed in next release, so you probably need to use master branch for now, until the next release later this month.
Sorry for the slow response, ACL issues are generally best raised at the ACL github, where those working on the software will be alerted promptly.