diff --git a/build/premake/premake5.lua b/build/premake/premake5.lua
index 519bf9ec99..0dcf5562f3 100644
--- a/build/premake/premake5.lua
+++ b/build/premake/premake5.lua
@@ -61,7 +61,7 @@ elseif not os.istarget("windows") then
 	end
 end
 
--- detect CPU architecture (simplistic, currently only supports x86, amd64 and ARM)
+-- detect CPU architecture (simplistic)
 arch = "x86"
 macos_arch = "x86_64"
 if _OPTIONS["android"] then
@@ -71,33 +71,33 @@ elseif os.istarget("windows") then
 		arch = "amd64"
 	end
 else
-	arch = os.getenv("HOSTTYPE")
-	-- Force x86_64 on Mac OS for now, as Spidermonkey 78 isn't Apple Silicon compatible.
+	os.execute(cc .. " -dumpmachine > .gccmachine.tmp")
+	local f = io.open(".gccmachine.tmp", "r")
+	local machine = f:read("*line")
+	f:close()
+	-- Special handling on mac os where xcode needs special flags.
 	if os.istarget("macosx") then
-		arch = "amd64"
-		macos_arch = "x86_64"
-	elseif arch == "x86_64" or arch == "amd64" then
-		arch = "amd64"
-	else
-		os.execute(cc .. " -dumpmachine > .gccmachine.tmp")
-		local f = io.open(".gccmachine.tmp", "r")
-		local machine = f:read("*line")
-		f:close()
-		if string.find(machine, "x86_64") == 1 or string.find(machine, "amd64") == 1 then
-			arch = "amd64"
-		elseif string.find(machine, "i.86") == 1 then
-			arch = "x86"
-		elseif string.find(machine, "arm") == 1 then
-			arch = "arm"
-		elseif string.find(machine, "aarch64") == 1 then
+		if string.find(machine, "arm64") then
 			arch = "aarch64"
-		elseif string.find(machine, "e2k") == 1 then
-			arch = "e2k"
-		elseif string.find(machine, "ppc64") == 1 or string.find(machine, "powerpc64") == 1 then
-			arch = "ppc64"
+			macos_arch = "arm64"
 		else
-			print("WARNING: Cannot determine architecture from GCC, assuming x86")
+			arch = "amd64"
+			macos_arch = "x86_64"
 		end
+	elseif string.find(machine, "x86_64") == 1 or string.find(machine, "amd64") == 1 then
+		arch = "amd64"
+	elseif string.find(machine, "i.86") == 1 then
+		arch = "x86"
+	elseif string.find(machine, "arm") == 1 then
+		arch = "arm"
+	elseif string.find(machine, "aarch64") == 1 then
+		arch = "aarch64"
+	elseif string.find(machine, "e2k") == 1 then
+		arch = "e2k"
+	elseif string.find(machine, "ppc64") == 1 or string.find(machine, "powerpc64") == 1 then
+		arch = "ppc64"
+	else
+		print("WARNING: Cannot determine architecture from GCC, assuming x86")
 	end
 end
 
@@ -327,8 +327,8 @@ function project_set_build_flags()
 				links { "gcov" }
 			end
 
-			-- MacOS 10.12 only supports processors with SSE 4.1, so enable that.
-			if os.istarget("macosx") then
+			-- MacOS 10.12 only supports intel processors with SSE 4.1, so enable that.
+			if os.istarget("macosx") and arch == "amd64" then
 				buildoptions { "-msse4.1" }
 			end
 
diff --git a/libraries/osx/build-osx-libs.sh b/libraries/osx/build-osx-libs.sh
index 0e4170c00b..058d83b6f9 100755
--- a/libraries/osx/build-osx-libs.sh
+++ b/libraries/osx/build-osx-libs.sh
@@ -36,14 +36,14 @@ FREETYPE_VERSION="freetype-2.10.4"
 OGG_VERSION="libogg-1.3.3"
 VORBIS_VERSION="libvorbis-1.3.7"
 # gloox requires GnuTLS, GnuTLS requires Nettle and GMP
-GMP_VERSION="gmp-6.2.0"
+GMP_VERSION="gmp-6.2.1"
 NETTLE_VERSION="nettle-3.6"
 # NOTE: remember to also update LIB_URL below when changing version
 GLOOX_VERSION="gloox-1.0.24"
 GNUTLS_VERSION="gnutls-3.6.15"
 # OS X only includes part of ICU, and only the dylib
 # NOTE: remember to also update LIB_URL below when changing version
-ICU_VERSION="icu4c-67_1"
+ICU_VERSION="icu4c-69_1"
 ENET_VERSION="enet-1.3.17"
 MINIUPNPC_VERSION="miniupnpc-2.2.2"
 SODIUM_VERSION="libsodium-1.0.18"
@@ -61,6 +61,7 @@ FMT_VERSION="7.1.3"
 
 export CC=${CC:="clang"} CXX=${CXX:="clang++"}
 export MIN_OSX_VERSION=${MIN_OSX_VERSION:="10.12"}
+export ARCH=${ARCH:=""}
 
 # The various libs offer inconsistent configure options, some allow
 # setting sysroot and OS X-specific options, others don't. Adding to
@@ -83,7 +84,7 @@ if [[ $MIN_OSX_VERSION && ${MIN_OSX_VERSION-_} ]]; then
 fi
 
 CFLAGS="$CFLAGS $C_FLAGS -fvisibility=hidden"
-CXXFLAGS="$CXXFLAGS $C_FLAGS -stdlib=libc++ -std=c++17 -msse4.1"
+CXXFLAGS="$CXXFLAGS $C_FLAGS -stdlib=libc++ -std=c++17"
 OBJCFLAGS="$OBJCFLAGS $C_FLAGS"
 OBJCXXFLAGS="$OBJCXXFLAGS $C_FLAGS"
 
@@ -94,16 +95,31 @@ ARCHLESS_CFLAGS=$CFLAGS
 ARCHLESS_CXXFLAGS=$CXXFLAGS
 ARCHLESS_LDFLAGS="$LDFLAGS -stdlib=libc++"
 
-CFLAGS="$CFLAGS -arch x86_64"
-CXXFLAGS="$CXXFLAGS -arch x86_64"
+# If ARCH isn't set, select either x86_64 or arm64
+if [ -z "${ARCH}" ]; then
+  if [ "`uname -m`" == "arm64" ]; then
+    ARCH="arm64"
+    # Some libs want this passed to configure for cross compilation.
+    HOST_PLATFORM="--host=aarch64-apple-darwin"
+  else
+    CXXFLAGS="$CXXFLAGS -msse4.1"
+    ARCH="x86_64"
+    # Some libs want this passed to configure for cross compilation.
+    HOST_PLATFORM="--host=x86_64-apple-darwin"
+  fi
+fi
 
-LDFLAGS="$LDFLAGS -arch x86_64"
+echo "ARCHITECTURE BREAKDOWN"
+echo $ARCH
+echo $HOST_PLATFORM
 
-# Some libs want this passed to configure for cross compilation.
-HOST_PLATFORM="--host=x86_64-apple-darwin"
+CFLAGS="$CFLAGS -arch $ARCH"
+CXXFLAGS="$CXXFLAGS -arch $ARCH"
+
+LDFLAGS="$LDFLAGS -arch $ARCH"
 
 # CMake doesn't seem to pick up on architecture with CFLAGS only
-CMAKE_FLAGS="-DCMAKE_OSX_ARCHITECTURES=x86_64"
+CMAKE_FLAGS="-DCMAKE_OSX_ARCHITECTURES=$ARCH"
 
 JOBS=${JOBS:="-j2"}
 
@@ -830,7 +846,7 @@ echo -e "Building ICU..."
 LIB_VERSION="${ICU_VERSION}"
 LIB_ARCHIVE="$LIB_VERSION-src.tgz"
 LIB_DIRECTORY="icu"
-LIB_URL="https://github.com/unicode-org/icu/releases/download/release-67-1/"
+LIB_URL="https://github.com/unicode-org/icu/releases/download/release-69-1/"
 
 mkdir -p icu
 pushd icu > /dev/null
@@ -1039,7 +1055,7 @@ then
 fi
 
 # Use the regular build script for SM.
-JOBS="$JOBS" ZLIB_DIR="$ZLIB_DIR" ./build.sh || die "Error building spidermonkey"
+JOBS="$JOBS" ZLIB_DIR="$ZLIB_DIR" ARCH="$ARCH" ./build.sh || die "Error building spidermonkey"
 
 popd > /dev/null
 
diff --git a/source/graphics/Color.cpp b/source/graphics/Color.cpp
index a5e4b142ea..49e6adad8f 100644
--- a/source/graphics/Color.cpp
+++ b/source/graphics/Color.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2022 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -83,8 +83,9 @@ void ColorActivateFastImpl()
 		ConvertRGBColorTo4ub = ConvertRGBColorTo4ubSSE;
 		return;
 	}
-#endif
+#elif defined(ARCH_X86_64)
 	debug_printf("No SSE available. Slow fallback routines will be used.\n");
+#endif
 }
 
 /**
diff --git a/source/tools/dist/build-osx-executable.sh b/source/tools/dist/build-osx-executable.sh
index 13a170c44b..cb83e52bb4 100755
--- a/source/tools/dist/build-osx-executable.sh
+++ b/source/tools/dist/build-osx-executable.sh
@@ -2,8 +2,7 @@
 
 # Build the Pyrogenesis executable, used to create the bundle and run the archiver.
 
-# TODO: is there anything to do for ARM support?
-export ARCH=${ARCH:="x86_64"}
+export ARCH=${ARCH:=$(uname -m)}
 
 # Set mimimum required OS X version, SDK location and tools
 # Old SDKs can be found at https://github.com/phracker/MacOSX-SDKs