[make] Use universal neko binaries for mac package

It can still be configured to specific architectures if needed, using
`PACKAGE_INSTALLER_MAC_ARCH`.

Makefile

@@ -181,19 +181,27 @@ xmldoc:
 $(INSTALLER_TMP_DIR):
 	mkdir -p $(INSTALLER_TMP_DIR)
 
-$(INSTALLER_TMP_DIR)/neko-osx64.tar.gz: $(INSTALLER_TMP_DIR)
-	wget -nv https://github.com/HaxeFoundation/neko/releases/download/$(NEKO_VERSION_TAG)/neko-$(NEKO_VERSION)-osx64.tar.gz -O installer/neko-osx64.tar.gz
+# Can be 'universal', 'arm64', or 'amd64'
+PACKAGE_INSTALLER_MAC_ARCH?=universal
+
+$(INSTALLER_TMP_DIR)/neko-osx.tar.gz: $(INSTALLER_TMP_DIR)
+	NEKO_ARCH_SUFFIX=$$(if [ "$(PACKAGE_INSTALLER_MAC_ARCH)" = "amd64" ]; then \
+		echo 64; \
+	else \
+		echo "-$(PACKAGE_INSTALLER_MAC_ARCH)"; \
+	fi); \
+	wget -nv https://github.com/HaxeFoundation/neko/releases/download/$(NEKO_VERSION_TAG)/neko-$(NEKO_VERSION)-osx$$NEKO_ARCH_SUFFIX.tar.gz -O installer/neko-osx.tar.gz
 
 # Installer
 
-package_installer_mac: $(INSTALLER_TMP_DIR)/neko-osx64.tar.gz package_unix
+package_installer_mac: $(INSTALLER_TMP_DIR)/neko-osx.tar.gz package_unix
 	$(eval OUTFILE := $(shell pwd)/$(PACKAGE_OUT_DIR)/$(PACKAGE_FILE_NAME)_installer.tar.gz)
 	$(eval PACKFILE := $(shell pwd)/$(PACKAGE_OUT_DIR)/$(PACKAGE_FILE_NAME)_bin.tar.gz)
 	$(eval VERSION := $(shell $(CURDIR)/$(HAXE_OUTPUT) -version 2>&1))
 	bash -c "rm -rf $(INSTALLER_TMP_DIR)/{resources,pkg,tgz,haxe.tar.gz}"
 	mkdir $(INSTALLER_TMP_DIR)/resources
 	# neko - unpack to change the dir name
-	cd $(INSTALLER_TMP_DIR)/resources && tar -zxvf ../neko-osx64.tar.gz
+	cd $(INSTALLER_TMP_DIR)/resources && tar -zxvf ../neko-osx.tar.gz
 	mv $(INSTALLER_TMP_DIR)/resources/neko* $(INSTALLER_TMP_DIR)/resources/neko
 	cd $(INSTALLER_TMP_DIR)/resources && tar -zcvf neko.tar.gz neko
 	# haxe - unpack to change the dir name