perf build: Install libapi 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 libapi build mirroring the libbpf and libsubcmd 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/20221109184914.1357295-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/.gitignore

@@ -39,6 +39,7 @@ trace/beauty/generated/
 pmu-events/pmu-events.c
 pmu-events/jevents
 feature/
+libapi/
 libbpf/
 libsubcmd/
 fixdep

tools/perf/Makefile.perf

@@ -241,7 +241,7 @@ sub-make: fixdep
 
 else # force_fixdep
 
-LIB_DIR         = $(srctree)/tools/lib/api/
+LIBAPI_DIR      = $(srctree)/tools/lib/api/
 TRACE_EVENT_DIR = $(srctree)/tools/lib/traceevent/
 LIBBPF_DIR      = $(srctree)/tools/lib/bpf/
 LIBSUBCMD_DIR   = $(srctree)/tools/lib/subcmd/
@@ -295,15 +295,9 @@ ifneq ($(OUTPUT),)
   TE_PATH=$(OUTPUT)
   PLUGINS_PATH=$(OUTPUT)
   LIBPERF_PATH=$(OUTPUT)
-ifneq ($(subdir),)
-  API_PATH=$(OUTPUT)/../lib/api/
-else
-  API_PATH=$(OUTPUT)
-endif
 else
   TE_PATH=$(TRACE_EVENT_DIR)
   PLUGINS_PATH=$(TRACE_EVENT_DIR)plugins/
-  API_PATH=$(LIB_DIR)
   LIBPERF_PATH=$(LIBPERF_DIR)
 endif
 
@@ -318,7 +312,14 @@ LIBTRACEEVENT_DYNAMIC_LIST = $(PLUGINS_PATH)libtraceevent-dynamic-list
 DYNAMIC_LIST_LDFLAGS               = -Xlinker --dynamic-list=$(LIBTRACEEVENT_DYNAMIC_LIST)
 LIBTRACEEVENT_DYNAMIC_LIST_LDFLAGS = $(if $(findstring -static,$(LDFLAGS)),,$(DYNAMIC_LIST_LDFLAGS))
 
-LIBAPI = $(API_PATH)libapi.a
+ifneq ($(OUTPUT),)
+  LIBAPI_OUTPUT = $(abspath $(OUTPUT))/libapi
+else
+  LIBAPI_OUTPUT = $(CURDIR)/libapi
+endif
+LIBAPI_DESTDIR = $(LIBAPI_OUTPUT)
+LIBAPI_INCLUDE = $(LIBAPI_DESTDIR)/include
+LIBAPI = $(LIBAPI_OUTPUT)/libapi.a
 export LIBAPI
 
 ifneq ($(OUTPUT),)
@@ -831,12 +832,14 @@ $(LIBTRACEEVENT)-clean:
 install-traceevent-plugins: libtraceevent_plugins
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) install_plugins
 
-$(LIBAPI): FORCE
-	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) $(OUTPUT)libapi.a
+$(LIBAPI): FORCE | $(LIBAPI_OUTPUT)
+	$(Q)$(MAKE) -C $(LIBAPI_DIR) O=$(LIBAPI_OUTPUT) \
+		DESTDIR=$(LIBAPI_DESTDIR) prefix= \
+		$@ install_headers
 
 $(LIBAPI)-clean:
 	$(call QUIET_CLEAN, libapi)
-	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
+	$(Q)$(RM) -r -- $(LIBAPI_OUTPUT)
 
 $(LIBBPF): FORCE | $(LIBBPF_OUTPUT)
 	$(Q)$(MAKE) -C $(LIBBPF_DIR) FEATURES_DUMP=$(FEATURE_DUMP_EXPORT) \
@@ -1047,7 +1050,7 @@ 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) $(LIBSUBCMD_OUTPUT):
+$(SKEL_TMP_OUT) $(LIBAPI_OUTPUT) $(LIBBPF_OUTPUT) $(LIBSUBCMD_OUTPUT):
 	$(Q)$(MKDIR) -p $@
 
 ifdef BUILD_BPF_SKEL