Add a test of cmdline usage strings - and make them saner
diff --git a/include/grpc/support/cmdline.h b/include/grpc/support/cmdline.h
index c2350a0..e5a2666 100644
--- a/include/grpc/support/cmdline.h
+++ b/include/grpc/support/cmdline.h
@@ -87,6 +87,8 @@
void gpr_cmdline_parse(gpr_cmdline *cl, int argc, char **argv);
/* Destroy the parser */
void gpr_cmdline_destroy(gpr_cmdline *cl);
+/* Get a string describing usage */
+char *gpr_cmdline_usage_string(gpr_cmdline *cl, const char *argv0);
#ifdef __cplusplus
}