Use more readable syntax for checking "aarch64" and "arm64" CPUs.

arch.mk

@@ -3,7 +3,10 @@ MACHINE := $(shell $(CC) -dumpmachine)
 ifneq (,$(findstring x86_64-,$(MACHINE)))
 	ARCH_X64 := 1
 	ARCH_CPU := x64
-else ifneq (,$(findstring arm64-,$(MACHINE))$(findstring aarch64-,$(MACHINE)))
+else ifneq (,$(findstring arm64-,$(MACHINE)))
+	ARCH_ARM64 := 1
+	ARCH_CPU := arm64
+else ifneq (,$(findstring aarch64-,$(MACHINE)))
 	ARCH_ARM64 := 1
 	ARCH_CPU := arm64
 else