build: Generate package-config file

Change-Id: Id3fc546c7fabe34bc31c4030d2e196f6d7f39090
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index cf70efe..552dc69 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -31,5 +31,8 @@
 libsdbusplus_la_LDFLAGS = $(SYSTEMD_LIBS) -version-info 1:0:0 -shared
 libsdbusplus_la_CXXFLAGS = $(SYSTEMD_CFLAGS)
 
+pkgconfiglibdir = ${libdir}/pkgconfig
+pkgconfiglib_DATA = sdbusplus.pc
+
 endif
 SUBDIRS = test tools