perf build: Install libsubcmd locally when building

The perf build currently has a '-Itools/lib' on the CC command
line. This causes issues as the libapi, libsubcmd, libtraceevent,
libbpf headers are all found via this path, making it impossible to
override include behavior. Change the libsubcmd build mirroring the
libbpf build, so that it is installed in a directory along with its
headers. A later change will modify the include behavior.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20221109184914.1357295-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/.gitignore

@@ -40,6 +40,7 @@ pmu-events/pmu-events.c
 pmu-events/jevents
 feature/
 libbpf/
+libsubcmd/
 fixdep
 libtraceevent-dynamic-list
 Documentation/doc.dep

tools/perf/Makefile.perf

@@ -244,7 +244,7 @@ else # force_fixdep
 LIB_DIR         = $(srctree)/tools/lib/api/
 TRACE_EVENT_DIR = $(srctree)/tools/lib/traceevent/
 LIBBPF_DIR      = $(srctree)/tools/lib/bpf/
-SUBCMD_DIR      = $(srctree)/tools/lib/subcmd/
+LIBSUBCMD_DIR   = $(srctree)/tools/lib/subcmd/
 LIBPERF_DIR     = $(srctree)/tools/lib/perf/
 DOC_DIR         = $(srctree)/tools/perf/Documentation/
 
@@ -294,7 +294,6 @@ strip-libs = $(filter-out -l%,$(1))
 ifneq ($(OUTPUT),)
   TE_PATH=$(OUTPUT)
   PLUGINS_PATH=$(OUTPUT)
-  SUBCMD_PATH=$(OUTPUT)
   LIBPERF_PATH=$(OUTPUT)
 ifneq ($(subdir),)
   API_PATH=$(OUTPUT)/../lib/api/
@@ -305,7 +304,6 @@ else
   TE_PATH=$(TRACE_EVENT_DIR)
   PLUGINS_PATH=$(TRACE_EVENT_DIR)plugins/
   API_PATH=$(LIB_DIR)
-  SUBCMD_PATH=$(SUBCMD_DIR)
   LIBPERF_PATH=$(LIBPERF_DIR)
 endif
 
@@ -332,7 +330,14 @@ LIBBPF_DESTDIR = $(LIBBPF_OUTPUT)
 LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
 LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
 
-LIBSUBCMD = $(SUBCMD_PATH)libsubcmd.a
+ifneq ($(OUTPUT),)
+  LIBSUBCMD_OUTPUT = $(abspath $(OUTPUT))/libsubcmd
+else
+  LIBSUBCMD_OUTPUT = $(CURDIR)/libsubcmd
+endif
+LIBSUBCMD_DESTDIR = $(LIBSUBCMD_OUTPUT)
+LIBSUBCMD_INCLUDE = $(LIBSUBCMD_DESTDIR)/include
+LIBSUBCMD = $(LIBSUBCMD_OUTPUT)/libsubcmd.a
 
 LIBPERF = $(LIBPERF_PATH)libperf.a
 export LIBPERF
@@ -849,11 +854,14 @@ $(LIBPERF)-clean:
 	$(call QUIET_CLEAN, libperf)
 	$(Q)$(MAKE) -C $(LIBPERF_DIR) O=$(OUTPUT) clean >/dev/null
 
-$(LIBSUBCMD): FORCE
-	$(Q)$(MAKE) -C $(SUBCMD_DIR) O=$(OUTPUT) $(OUTPUT)libsubcmd.a
+$(LIBSUBCMD): FORCE | $(LIBSUBCMD_OUTPUT)
+	$(Q)$(MAKE) -C $(LIBSUBCMD_DIR) O=$(LIBSUBCMD_OUTPUT) \
+		DESTDIR=$(LIBSUBCMD_DESTDIR) prefix= \
+		$@ install_headers
 
 $(LIBSUBCMD)-clean:
-	$(Q)$(MAKE) -C $(SUBCMD_DIR) O=$(OUTPUT) clean
+	$(call QUIET_CLEAN, libsubcmd)
+	$(Q)$(RM) -r -- $(LIBSUBCMD_OUTPUT)
 
 help:
 	@echo 'Perf make targets:'
@@ -1039,7 +1047,7 @@ SKELETONS += $(SKEL_OUT)/bperf_cgroup.skel.h $(SKEL_OUT)/func_latency.skel.h
 SKELETONS += $(SKEL_OUT)/off_cpu.skel.h $(SKEL_OUT)/lock_contention.skel.h
 SKELETONS += $(SKEL_OUT)/kwork_trace.skel.h
 
-$(SKEL_TMP_OUT) $(LIBBPF_OUTPUT):
+$(SKEL_TMP_OUT) $(LIBBPF_OUTPUT) $(LIBSUBCMD_OUTPUT):
 	$(Q)$(MKDIR) -p $@
 
 ifdef BUILD_BPF_SKEL