Use configure option yaml path to generate elog-errors.hpp

Add a config variable that can be passed via a recipe to
point the parser to a directory where the error yaml files are.
Rename elog-gen.hpp to elog-errors.hpp, which better matches the
exception error log file names.
Include elog-gen.hpp in elog.hpp so that callers that need to
create and commit error logs only need to include one header file.

Change-Id: Ie3cd65ac761c1f7b2c99c50a2273859283a5ab4b
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/configure.ac b/configure.ac
index c99fc1f..10655ed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -63,6 +63,14 @@
 AC_DEFINE(OBJ_LOGGING, "/xyz/openbmc_project/logging", [The log manager DBus object path.])
 AC_DEFINE(OBJ_INTERNAL, "/xyz/openbmc_project/logging/internal/manager", [The private log manager DBus object path.])
 AC_DEFINE(OBJ_ENTRY, "/xyz/openbmc_project/logging/entry", [The log entry DBus object path.])
+
+AC_ARG_VAR(YAML_DIR_TEST, [The path to the test error yaml files.])
+AS_IF([test "x$YAML_DIR_TEST" == "x"], \
+    [YAML_DIR_TEST="${srcdir}/tools/"])
+AC_ARG_VAR(YAML_DIR, [The path to the yaml error files.])
+AS_IF([test "x$YAML_DIR" == "x"], \
+    [YAML_DIR="None"])
+
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([Makefile test/Makefile])
 AC_CONFIG_FILES([phosphor-logging.pc])