Adapt for building against LLVM/Clang with monolithic libraries.

--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -338,7 +338,7 @@ $(OUTPUT)test-llvm.bin:
 	$(BUILDXX) -std=gnu++14 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
-		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
+		$(shell $(LLVM_CONFIG) --libs)			\
 		$(shell $(LLVM_CONFIG) --system-libs)		\
 		> $(@:.bin=.make.output) 2>&1
 
@@ -351,10 +351,7 @@ $(OUTPUT)test-clang.bin:
 	$(BUILDXX) -std=gnu++14					\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
-		-Wl,--start-group -lclangBasic -lclangDriver	\
-		  -lclangFrontend -lclangEdit -lclangLex	\
-		  -lclangAST -Wl,--end-group 			\
-		$(shell $(LLVM_CONFIG) --libs Core option)	\
+		-lclang-cpp $(shell $(LLVM_CONFIG) --libs)	\
 		$(shell $(LLVM_CONFIG) --system-libs)		\
 		> $(@:.bin=.make.output) 2>&1
 
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -416,14 +416,11 @@ EXTLIBS := $(call filter-out,$(EXCLUDE_EXTLIBS),$(EXTLIBS))
 LIBS = -Wl,--whole-archive $(PERFLIBS) $(EXTRA_PERFLIBS) -Wl,--no-whole-archive -Wl,--start-group $(EXTLIBS) -Wl,--end-group
 
 ifeq ($(USE_CLANG), 1)
-  CLANGLIBS_LIST = AST Basic CodeGen Driver Frontend Lex Tooling Edit Sema Analysis Parse Serialization
-  CLANGLIBS_NOEXT_LIST = $(foreach l,$(CLANGLIBS_LIST),$(shell $(LLVM_CONFIG) --libdir)/libclang$(l))
-  LIBCLANG = $(foreach l,$(CLANGLIBS_NOEXT_LIST),$(wildcard $(l).a $(l).so))
-  LIBS += -Wl,--start-group $(LIBCLANG) -Wl,--end-group
+  LIBS += -lclang-cpp
 endif
 
 ifeq ($(USE_LLVM), 1)
-  LIBLLVM = $(shell $(LLVM_CONFIG) --libs all) $(shell $(LLVM_CONFIG) --system-libs)
+  LIBLLVM = $(shell $(LLVM_CONFIG) --libs) $(shell $(LLVM_CONFIG) --system-libs)
   LIBS += -L$(shell $(LLVM_CONFIG) --libdir) $(LIBLLVM)
 endif