external: Rework clang to support multiple versions

Author: mpe

external/clang/Makefile

@@ -1,30 +1,42 @@
 help:
 	@echo "clang"
 	@echo "Available targets:"
-	@echo "  download       # download and unpack clang"
+	@echo "  download       # download and unpack default clang version"
+	@echo "  download-all   # download and unpack all clang versions"
 	@echo ""
+	@echo "Download additional versions with:"
+	@echo "  $ make llvm-<version>"
 
-VERSION := 14.0.0
+define TEMPLATE =
+llvm-$(1):
+	rm -f llvm-$(1).tar.xz
+	wget --no-verbose -O llvm-$(1).tar.xz https://github.com/llvm/llvm-project/releases/download/llvmorg-$(1)/clang+llvm-$(1)-powerpc64le-linux-rhel-8.4.tar.xz
+	tar -xf llvm-$(1).tar.xz
+	touch $$@
+	rm -rf llvm-$(1).tar.xz llvm-$(1)
+	mv clang+llvm-* llvm-$(1)
 
-clang.tar.xz:
-	wget --no-verbose -O $@.tmp https://github.com/llvm/llvm-project/releases/download/llvmorg-$(VERSION)/clang+llvm-$(VERSION)-powerpc64le-linux-rhel-7.9.tar.xz
-	mv $@.tmp $@
+CLEAN_DIRS += llvm-$(1)
+ALL_TARGETS += llvm-$(1)
+endef
 
-install/bin/clang: clang.tar.xz
-	rm -rf install
-	tar -xf clang.tar.xz
-	mv clang+llvm-* install
+$(eval $(call TEMPLATE,14.0.6))
+$(eval $(call TEMPLATE,15.0.7))
+$(eval $(call TEMPLATE,16.0.0-rc2))
 
-download: install/bin/clang
+# Only download clang-15 by default
+download: llvm-15.0.7
 
 prepare: download
 
+download-all: $(ALL_TARGETS)
+
 build:
 
 clean:
 	@:
 
 distclean: clean
-	rm -rf install clang.tar.xz
+	rm -rf $(CLEAN_DIRS) *.tar.xz
 
 .PHONY: download prepare build clean distclean help