build:  Add pkg-config for clients

Provide a pkg-config for clients using our headers.

Partially resolves openbmc/openbmc#1106

Change-Id: I185da26a0034b4bb315d2b279c776eea87c14a82
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/Makefile.am b/Makefile.am
index d0189de..a2b4ca5 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -52,4 +52,7 @@
 elog-lookup.cpp: $(REQ_FILES_TO_GEN)
 	$(AM_V_at)$(PYTHON) ${abs_srcdir}/tools/elog-gen.py -y ${abs_srcdir}/${ELOG_YAML_DIR} -t ${abs_srcdir}/${ELOG_TEMPLATE_DIR} -m $(LOOKUP_MAKO) -o ${abs_srcdir}/elog-lookup.cpp
 
+pkgconfiglibdir = ${libdir}/pkgconfig
+pkgconfiglib_DATA = phosphor-logging.pc
+
 SUBDIRS = test