Improve LLVM deps build

- Remove duplication in git clone code
- Copy over the ability to check out a specific clang/lldb branch from kf/gallium

Author: Keno

deps/Makefile

@@ -583,36 +583,33 @@ ifneq ($(LLVM_LLDB_TAR),)
 	mkdir -p llvm-$(LLVM_VER)/tools/lldb && \
 	$(TAR) -C llvm-$(LLVM_VER)/tools/lldb --strip-components 1 -xf $(LLVM_LLDB_TAR)
 endif # LLVM_LLDB_TAR
-else
+else # LLVM_VER
 ifeq ($(BUILD_LLVM_CLANG),1)
 	([ ! -d llvm-$(LLVM_VER)/tools/clang ] && \
 		git clone $(LLVM_GIT_URL_CLANG) llvm-$(LLVM_VER)/tools/clang  ) || \
 		(cd llvm-$(LLVM_VER)/tools/clang  && \
 		git pull --ff-only)
+	([ ! -d llvm-$(LLVM_VER)/projects/compiler-rt ] && \
+                git clone $(LLVM_GIT_URL_COMPILER_RT) llvm-$(LLVM_VER)/projects/compiler-rt  ) || \
+                (cd llvm-$(LLVM_VER)/projects/compiler-rt  && \
+                git pull --ff-only)
+ifneq ($(LLVM_GIT_VER_CLANG),)
+	(cd llvm-$(LLVM_VER)/tools/clang && \
+		git checkout $(LLVM_GIT_VER_CLANG))
+endif # LLVM_GIT_VER_CLANG
 endif # BUILD_LLVM_CLANG
 ifeq ($(BUILD_LLDB),1)
 	([ ! -d llvm-$(LLVM_VER)/tools/lldb ] && \
 		git clone $(LLVM_GIT_URL_LLDB) llvm-$(LLVM_VER)/tools/lldb  ) || \
 		(cd llvm-$(LLVM_VER)/tools/lldb  && \
 		git pull --ff-only)
+ifneq ($(LLVM_GIT_VER_LLDB),)
+	(cd $(LLVM_VER)/tools/lldb && \
+		git checkout $(LLVM_GIT_VER_LLDB))
+endif # LLVM_GIT_VER_CLANG
 endif # BUILD_LLDB
 endif # LLVM_VER
-ifeq ($(LLVM_VER),svn)
-ifeq ($(BUILD_LLVM_CLANG),1)
-	([ ! -d llvm-$(LLVM_VER)/tools/clang ] && \
-		git clone $(LLVM_GIT_URL_CLANG) llvm-$(LLVM_VER)/tools/clang  ) || \
-		(cd llvm-$(LLVM_VER)/tools/clang  && \
-		git pull --ff-only)
-	([ ! -d llvm-$(LLVM_VER)/projects/compiler-rt ] && \
-		git clone $(LLVM_GIT_URL_COMPILER_RT) llvm-$(LLVM_VER)/projects/compiler-rt  ) || \
-		(cd llvm-$(LLVM_VER)/projects/compiler-rt  && \
-		git pull --ff-only)
-ifneq ($(LLVM_CLANG_VER),)
-	(cd llvm-$(LLVM_VER) && \
-		git checkout $(LLVM_GIT_VER))
-endif # LLVM_CLANG_VER
-endif # BUILD_LLVM_CLANG
-endif # LLVM_VER
+	touch -c $@
 
 # Apply version-specific LLVM patches
 ifeq ($(LLVM_VER),3.3)