Add mesosphere (VERY VERY WIP)

mesosphere/config/arch/arm64/arch.mk

@@ -0,0 +1,25 @@
+ifeq ($(strip $(DEVKITPRO)),)
+
+PREFIX			:=	aarch64-none-elf-
+
+export CC		:=	$(PREFIX)gcc
+export CXX		:=	$(PREFIX)g++
+export AS		:=	$(PREFIX)as
+export AR		:=	$(PREFIX)gcc-ar
+export OBJCOPY	:=	$(PREFIX)objcopy
+
+ISVC=$(or $(VCBUILDHELPER_COMMAND),$(MSBUILDEXTENSIONSPATH32),$(MSBUILDEXTENSIONSPATH))
+
+ifneq (,$(ISVC))
+	ERROR_FILTER	:=	2>&1 | sed -e 's/\(.[a-zA-Z]\+\):\([0-9]\+\):/\1(\2):/g'
+endif
+
+else
+include $(DEVKITPRO)/devkitA64/base_tools
+endif
+
+ARCH_SETTING			:= -march=armv8-a -mgeneral-regs-only
+ARCH_DEFINES			:= -DMESOSPHERE_ARCH_ARM64
+ARCH_CFLAGS				:=
+ARCH_CXXFLAGS			:=
+ARCH_SOURCE_DIRS 		:= source/arch/arm64