Syslog: enabled logging of send errors. The ngx_cycle->log is used when sending the message. This allows to log syslog send errors in another log. Logging to syslog after its cleanup handler has been executed was prohibited. Previously, this was possible from ngx_destroy_pool(), which resulted in error messages caused by attempts to write into the closed socket. The "processing" flag is renamed to "busy" to better match its semantics.

--- a/src/core/ngx_syslog.h
+++ b/src/core/ngx_syslog.h
@@ -16,7 +16,7 @@ typedef struct {
 
     ngx_addr_t        server;
     ngx_connection_t  conn;
-    ngx_uint_t        processing;  /* unsigned processing:1; */
+    ngx_uint_t        busy;  /* unsigned busy:1; */
 } ngx_syslog_peer_t;