tools lib traceevent: Added support for pkg-config

This patch implements integration with pkg-config framework.  pkg-config
can be used by the library users to determine required CFLAGS and
LDFLAGS in order to use the library

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181130154647.022471992@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/Makefile

@@ -25,6 +25,7 @@ endef
 $(call allow-override,CC,$(CROSS_COMPILE)gcc)
 $(call allow-override,AR,$(CROSS_COMPILE)ar)
 $(call allow-override,NM,$(CROSS_COMPILE)nm)
+$(call allow-override,PKG_CONFIG,pkg-config)
 
 EXT = -std=gnu99
 INSTALL = install
@@ -47,6 +48,8 @@ prefix ?= /usr/local
 libdir = $(prefix)/$(libdir_relative)
 man_dir = $(prefix)/share/man
 man_dir_SQ = '$(subst ','\'',$(man_dir))'
+pkgconfig_dir ?= $(word 1,$(shell $(PKG_CONFIG) 		\
+			--variable pc_path pkg-config | tr ":" " "))
 
 export man_dir man_dir_SQ INSTALL
 export DESTDIR DESTDIR_SQ
@@ -270,7 +273,19 @@ define do_generate_dynamic_list_file
 	fi
 endef
 
-install_lib: all_cmd install_plugins
+PKG_CONFIG_FILE = libtraceevent.pc
+define do_install_pkgconfig_file
+	if [ -n "${pkgconfig_dir}" ]; then 					\
+		cp -f ${PKG_CONFIG_FILE}.template ${PKG_CONFIG_FILE}; 		\
+		sed -i "s|INSTALL_PREFIX|${1}|g" ${PKG_CONFIG_FILE}; 		\
+		sed -i "s|LIB_VERSION|${EVENT_PARSE_VERSION}|g" ${PKG_CONFIG_FILE}; \
+		$(call do_install,$(PKG_CONFIG_FILE),$(pkgconfig_dir),644); 	\
+	else 									\
+		(echo Failed to locate pkg-config directory) 1>&2;		\
+	fi
+endef
+
+install_lib: all_cmd install_plugins install_pkgconfig
 	$(call QUIET_INSTALL, $(LIB_TARGET)) \
 		$(call do_install_mkdir,$(libdir_SQ)); \
 		cp -fpR $(LIB_INSTALL) $(DESTDIR)$(libdir_SQ)
@@ -279,6 +294,10 @@ install_plugins: $(PLUGINS)
 	$(call QUIET_INSTALL, trace_plugins) \
 		$(call do_install_plugins, $(PLUGINS))
 
+install_pkgconfig:
+	$(call QUIET_INSTALL, $(PKG_CONFIG_FILE)) \
+		$(call do_install_pkgconfig_file,$(prefix))
+
 install_headers:
 	$(call QUIET_INSTALL, headers) \
 		$(call do_install,event-parse.h,$(prefix)/include/traceevent,644); \
@@ -289,8 +308,9 @@ install: install_lib
 
 clean:
 	$(call QUIET_CLEAN, libtraceevent) \
-		$(RM) *.o *~ $(TARGETS) *.a *.so $(VERSION_FILES) .*.d .*.cmd \
+		$(RM) *.o *~ $(TARGETS) *.a *.so $(VERSION_FILES) .*.d .*.cmd; \
-		$(RM) TRACEEVENT-CFLAGS tags TAGS
+		$(RM) TRACEEVENT-CFLAGS tags TAGS; \
+		$(RM) $(PKG_CONFIG_FILE)
 
 PHONY += force plugins
 force:

tools/lib/traceevent/libtraceevent.pc.template

@@ -0,0 +1,10 @@
+prefix=INSTALL_PREFIX
+libdir=${prefix}/lib64
+includedir=${prefix}/include/traceevent
+
+Name: libtraceevent
+URL: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+Description: Linux kernel trace event library
+Version: LIB_VERSION
+Cflags: -I${includedir}
+Libs: -L${libdir} -ltraceevent