SuperSlicer/deps/PNG/macos-arm64.patch

Based on https://github.com/vespakoen/libpng to work around until
https://github.com/glennrp/libpng/pull/354 is resolved.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4db9bb87d..9099d1edf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -82,10 +82,22 @@ option(PNG_HARDWARE_OPTIMIZATIONS "Enable Hardware Optimizations" ON)
 set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
 set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")
 
+# CMake currently sets CMAKE_SYSTEM_PROCESSOR to one of x86_64 or arm64 on macOS,
+# based upon the OS architecture, not the target architecture. As such, we need
+# to check CMAKE_OSX_ARCHITECTURES to identify which hardware-specific flags to
+# enable. Note that this will fail if you attempt to build a universal binary in
+# a single cmake invokation.
+if (APPLE AND CMAKE_OSX_ARCHITECTURES)
+  set(TARGET_ARCH ${CMAKE_OSX_ARCHITECTURES})
+else()
+  set(TARGET_ARCH ${CMAKE_SYSTEM_PROCESSOR})
+endif()
+
+
 if(PNG_HARDWARE_OPTIMIZATIONS)
 # set definitions and sources for arm
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
-  CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
+if(TARGET_ARCH MATCHES "^arm" OR
+   TARGET_ARCH MATCHES "^aarch64")
   set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
   set(PNG_ARM_NEON "check" CACHE STRING "Enable ARM NEON optimizations:
      check: (default) use internal checking code;
@@ -114,8 +126,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" OR
 endif()
 
 # set definitions and sources for powerpc
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "^ppc64*" )
+if(TARGET_ARCH MATCHES "^powerpc*" OR
+       TARGET_ARCH MATCHES "^ppc64*" )
   set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
   set(PNG_POWERPC_VSX "on" CACHE STRING "Enable POWERPC VSX optimizations:
      off: disable the optimizations.")
@@ -138,8 +150,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc*" OR
 endif()
 
 # set definitions and sources for intel
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "^x86_64*" )
+if(TARGET_ARCH MATCHES "^i?86" OR
+       TARGET_ARCH MATCHES "^x86_64*" )
   set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
   set(PNG_INTEL_SSE "on" CACHE STRING "Enable INTEL_SSE optimizations:
      off: disable the optimizations")
@@ -162,8 +174,8 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "^i?86" OR
 endif()
 
 # set definitions and sources for MIPS
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "mipsel*" OR
-	CMAKE_SYSTEM_PROCESSOR MATCHES "mips64el*" )
+if(TARGET_ARCH MATCHES "mipsel*" OR
+        TARGET_ARCH MATCHES "mips64el*" )
   set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
   set(PNG_MIPS_MSA "on" CACHE STRING "Enable MIPS_MSA optimizations:
      off: disable the optimizations")