Revert arch.mk refactor.

arch.mk

@@ -1,34 +1,34 @@
 MACHINE := $(shell $(CC) -dumpmachine)
-MACHINE_LIST := $(subst -, ,$(MACHINE))
-MACHINE_ARCH := $(word 1, $(MACHINE_LIST))
-MACHINE_VENDOR := $(word 2, $(MACHINE_LIST))
-MACHINE_OS := $(word 3, $(MACHINE_LIST))
 
-ifeq ($(MACHINE_ARCH),x86_64)
+ifneq (,$(findstring x86_64-,$(MACHINE)))
 	ARCH_X64 := 1
 	ARCH_NAME := x64
-else ifeq ($(MACHINE_ARCH),arm64)
+else ifneq (,$(findstring arm64-,$(MACHINE)))
 	ARCH_ARM64 := 1
 	ARCH_NAME := arm64
 else
-$(error CPU architecture $(MACHINE_ARCH) not supported)
+$(error Could not determine CPU architecture of $(MACHINE))
 endif
 
-ifneq (,$(findstring darwin,$(MACHINE_OS)))
+ifneq (,$(findstring -darwin,$(MACHINE)))
 	ARCH_MAC := 1
 	ARCH_OS_NAME := mac
-else ifneq (,$(findstring mingw32,$(MACHINE_OS)))
+else ifneq (,$(findstring -mingw32,$(MACHINE)))
 	ARCH_WIN := 1
 	ARCH_OS_NAME := win
-else ifneq (,$(findstring linux,$(MACHINE_OS)))
+else ifneq (,$(findstring -linux,$(MACHINE)))
 	ARCH_LIN := 1
 	ARCH_OS_NAME := lin
 else
-$(error Operating system $(MACHINE_OS) not supported)
+$(error Could not determine operating system of $(MACHINE))
 endif
 
 
-ARCH_FULL_NAME := $(ARCH_OS_NAME)
-ifndef ARCH_X64
-	ARCH_FULL_NAME := $(ARCH_FULL_NAME)_$(ARCH_NAME)
+# The architecture "full name" is used in package filenames.
+# Examples: win, lin, mac, mac_arm64
+ifdef ARCH_X64
+	# Omit arch name for x64
+	ARCH_FULL_NAME := $(ARCH_OS_NAME)
+else
+	ARCH_FULL_NAME := $(ARCH_OS_NAME)_$(ARCH_NAME)
 endif