Use full paths to enable bitbake builds of mako files

The mako python library requires full paths to the
template files so use ${abs_srdir} to get full paths

Change-Id: If322c66eedc7584633b18b137ad732be212359d6
Signed-off-by: Andrew Geissler <andrewg@us.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index 4009061..ba54f20 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -16,15 +16,15 @@
 # systemd required for journal interfaces
 logging_test_LDFLAGS = $(SYSTEMD_LIBS)
 
-ELOG_YAML ?= ${srcdir}/elog.yaml
-ELOG_MAKO ?= ${srcdir}/elog-gen-template.mako.hpp
-REQ_FILES_TO_GEN ?= ${srcdir}/elog-gen.py $(ELOG_YAML) $(ELOG_MAKO)
+ELOG_YAML ?= ${abs_srcdir}/elog.yaml
+ELOG_MAKO ?= ${abs_srcdir}/elog-gen-template.mako.hpp
+REQ_FILES_TO_GEN ?= ${abs_srcdir}/elog-gen.py $(ELOG_YAML) $(ELOG_MAKO)
 
 # Be sure to package up the required script, yaml, and mako template to
 # generate the header file
 EXTRA_DIST = $(REQ_FILES_TO_GEN)
 
 elog-gen.hpp: $(REQ_FILES_TO_GEN)
-	$(AM_V_at)${srcdir}/elog-gen.py -e $(ELOG_YAML) -m $(ELOG_MAKO) -o ${srcdir}/elog-gen.hpp
+	$(AM_V_at)${abs_srcdir}/elog-gen.py -e $(ELOG_YAML) -m $(ELOG_MAKO) -o ${abs_srcdir}/elog-gen.hpp
 
 SUBDIRS = test
\ No newline at end of file