Builds for wrong-architecture on M1 macs

[jherico]

A user reported a problem building the Vulkan Sample repository after an update to the most recent release of ASTC.

The linker errors shown indicate that the file is being built for an x86_64 architecture even though it's building on an arm64 arch.

I was able to reproduce this by executing the following

ec2-user@ip-172-31-45-6 astc % cmake -B build -DASTCENC_ISA_NATIVE=ON -DASTCENC_UNIVERSAL_BUILD=OFF
--   AVX2 backend     - OFF
--   SSE4.1 backend   - OFF
--   SSE2 backend     - OFF
--   NEON backend     - OFF
--   NONE backend     - OFF
--   NATIVE backend   - ON
--   Universal bin    - OFF
--   Invariance       - ON
--   Shared libs      - OFF
--   Decompressor     - OFF
--   Diagnostics      - OFF
--   ASAN             - OFF
--   Unit tests       - OFF
-- Configuring done (0.1s)
-- Generating done (0.0s)
-- Build files have been written to: /Users/ec2-user/Vulkan-Samples/third_party/astc/build
ec2-user@ip-172-31-45-6 astc % cmake --build build --parallel
[  3%] Building CXX object Source/CMakeFiles/astcenc-native-veneer.dir/astcenccli_entry.cpp.o
<snip>
[100%] Linking CXX executable astcenc-native
[100%] Built target astcenc-native

ec2-user@ip-172-31-45-6 astc % file ./build/Source/astcenc-native
./build/Source/astcenc-native: Mach-O 64-bit executable x86_64
ec2-user@ip-172-31-45-6 astc % uname -a
Darwin ip-172-31-45-6.ec2.internal 23.3.0 Darwin Kernel Version 23.3.0: Wed Dec 20 21:33:31 PST 2023; root:xnu-10002.81.5~7/RELEASE_ARM64_T8112 arm64

I've got a fix that works around it by forcing the OSX_ARCHITECTURES property of the target to arm64 in the case where we're building on Apple and running on M1 hardware or later.

[solidpixel]

Thanks - will take a look, but might not get around to it until later in the month.

[KaperD]

I think that there should be elseif(NOT ${ASTCENC_ISA_SIMD} MATCHES "none" AND NOT ${ASTCENC_ISA_SIMD} MATCHES "native")

[solidpixel]

Fixed in 71a55e7