perf build: Update feature check for clang and llvm

Perf build auto-detects features and packages already installed for its
build. This is done in directory tools/build/feature. This directory
contains small sample programs. When they successfully compile the
necessary prereqs in form of libraries and header files are present.

Such a check is also done for llvm and clang. And the checks fail.

Fix this and update to the latest C++ standard and use the new library
provided by clang (which contains new packaging) s/ee this link for
reference:

 https://fedoraproject.org/wiki/Changes/Stop-Shipping-Individual-Component-Libraries-In-clang-lib-Package

Output before:
 # rm -f ./test-clang.bin; make test-clang.bin; ./test-clang.bin; \
	ll test-clang.make.output
 g++  -MD -Wall -Werror -o test-clang.bin test-clang.cpp \
	 	> test-clang.make.output 2>&1 -std=gnu++14 \
	-I/usr/include 		\
	-L/usr/lib64		\
	-Wl,--start-group -lclangBasic -lclangDriver	\
	  -lclangFrontend -lclangEdit -lclangLex	\
	  -lclangAST -Wl,--end-group 			\
	-lLLVM-16	\
			\
	> test-clang.make.output 2>&1
 make: *** [Makefile:356: test-clang.bin] Error 1
 -bash: ./test-clang.bin: No such file or directory
 -rw-r--r--. 1 root root 252041 Jul 12 09:56 test-clang.make.output
 #

File test-clang.make.output contains many lines of unreferenced
symbols.

Output after:
 # rm -f ./test-clang.bin; make test-clang.bin; ./test-clang.bin; \
	cat test-clang.make.output
 g++  -MD -Wall -Werror -o test-clang.bin test-clang.cpp \
	 > test-clang.make.output 2>&1 -std=gnu++17	\
	-I/usr/include 		\
	-L/usr/lib64		\
	-Wl,--start-group -lclang-cpp -Wl,--end-group	\
	-lLLVM-16	\
			\
	> test-clang.make.output 2>&1
 #

Committer notes:

Test it in the tools/build/feature directory, and have clang-devel and
llvm-devel installed.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lore.kernel.org/r/20230725150347.3479291-1-tmricht@linux.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/Makefile

@@ -340,7 +340,7 @@ $(OUTPUT)test-jvmti-cmlr.bin:
 	$(BUILD)
 
 $(OUTPUT)test-llvm.bin:
-	$(BUILDXX) -std=gnu++14 				\
+	$(BUILDXX) -std=gnu++17 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
@@ -348,17 +348,15 @@ $(OUTPUT)test-llvm.bin:
 		> $(@:.bin=.make.output) 2>&1
 
 $(OUTPUT)test-llvm-version.bin:
-	$(BUILDXX) -std=gnu++14					\
+	$(BUILDXX) -std=gnu++17					\
 		-I$(shell $(LLVM_CONFIG) --includedir)		\
 		> $(@:.bin=.make.output) 2>&1
 
 $(OUTPUT)test-clang.bin:
-	$(BUILDXX) -std=gnu++14					\
+	$(BUILDXX) -std=gnu++17					\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
-		-Wl,--start-group -lclangBasic -lclangDriver	\
-		  -lclangFrontend -lclangEdit -lclangLex	\
-		  -lclangAST -Wl,--end-group 			\
+		-Wl,--start-group -lclang-cpp -Wl,--end-group	\
 		$(shell $(LLVM_CONFIG) --libs Core option)	\
 		$(shell $(LLVM_CONFIG) --system-libs)		\
 		> $(@:.bin=.make.output) 2>&1