logging: introduce log levels at caller site
This introduces a new LOGP() macro together with LOGL_* definition to
support multiple log levels (severities) throughout the codebase.
Please note that the actual logging system does not use them yet,
in this patch we simply introduce the new macros at the caller site.
diff --git a/openbsc/src/rtp_proxy.c b/openbsc/src/rtp_proxy.c
index 59c0735..bfd4948 100644
--- a/openbsc/src/rtp_proxy.c
+++ b/openbsc/src/rtp_proxy.c
@@ -211,7 +211,7 @@
written = write(rss->bfd.fd, msg->data, msg->len);
if (written < msg->len) {
- perror("short write");
+ LOGP(DMIB, LOGL_ERROR, "short write");
msgb_free(msg);
return -EIO;
}