nme setup fails on M1 Mac

[exastencil]

I'm on an M1 MacBook Pro (64-bit ARM, with 64-bit x86 support through Rosetta). Haxe is installed though homebrew, and haxelib put somewhere with write access.

When I run haxelib run nme setup it seems to correctly build the 64-bit version

Build mac, link=ndll arch=m64
haxelib run hxcpp ToolkitBuild.xml -Dmac -DHXCPP_M64

but when it gets tothe 32-bit version it errors:

Build mac, link=ndll arch=m32
haxelib run hxcpp ToolkitBuild.xml -Dmac -DHXCPP_M32
...
Error: In file included from ./src/common/Utils.cpp:25:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk/System/Library/Frameworks/CoreServices.framework/Headers/CoreServices.h:23:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk/System/Library/Frameworks/CoreServices.framework/Frameworks/AE.framework/Headers/AE.h:20:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk/System/Library/Frameworks/CoreServices.framework/Frameworks/CarbonCore.framework/Headers/CarbonCore.h:35:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk/System/Library/Frameworks/CoreServices.framework/Frameworks/CarbonCore.framework/Headers/FixMath.h:86:6: error: "Unknown architecture."
    #error "Unknown architecture."
     ^

Is there a way to only build the 64-bit version, or perhaps the ARM64 version on M1 Macs?