Remove redefinitions of toolchain, and hardcoded optimisations. Replace GENie
 build target with devel/genie binary. Add Clang ARM64 support.

--- makefile.orig	2023-10-23 15:53:41 UTC
+++ makefile
@@ -448,9 +448,9 @@ ifneq ($(TARGETOS),asmjs)
 endif
 
 ifneq ($(TARGETOS),asmjs)
-CC := $(SILENT)gcc
-LD := $(SILENT)g++
-CXX:= $(SILENT)g++
+CC ?= $(SILENT)gcc
+LD ?= $(SILENT)g++
+CXX ?= $(SILENT)g++
 endif
 
 #-------------------------------------------------
@@ -620,11 +620,6 @@ endif
 SYMBOLS = 1
 endif
 
-# specify a default optimization level if none explicitly stated
-ifndef OPTIMIZE
-OPTIMIZE = 3
-endif
-
 # set the symbols level
 ifdef SYMBOLS
 PARAMS += --SYMBOLS='$(SYMBOLS)'
@@ -1078,7 +1073,7 @@ endif
 NEW_GIT_VERSION := unknown
 endif
 
-GENIE := 3rdparty/genie/bin/$(GENIEOS)/genie$(EXE)
+GENIE := %%GENIE_PREFIX%%genie
 
 ifeq ($(TARGET),$(SUBTARGET_FULL))
 FULLTARGET := $(TARGET)
@@ -1412,6 +1407,11 @@ $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang/Makefile: make
 
 $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang/Makefile: makefile $(SCRIPTS) $(GENIE)
 	$(SILENT) $(GENIE) $(PARAMS) $(TARGET_PARAMS) --gcc=freebsd-clang --gcc_version=$(CLANG_VERSION) $(MAKETYPE)
+
+.PHONY: freebsd_arm64_clang
+freebsd_arm64_clang: generate $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang/Makefile
+	$(SILENT) $(MAKE) -C $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang config=$(CONFIG)64 precompile
+	$(SILENT) $(MAKE) -C $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang config=$(CONFIG)64
 
 .PHONY: freebsd_x64_clang
 freebsd_x64_clang: generate $(PROJECTDIR)/$(MAKETYPE)-freebsd-clang/Makefile