Fixed counting of sent bytes in the send chain functions on EINTR. Previously, a value of the "send" variable wasn't properly adjusted in a rare case when syscall was interrupted by a signal. As a result, these functions could send less data than the limit allows.

--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -378,6 +378,7 @@ ngx_freebsd_sendfile_chain(ngx_connectio
         }
 
         if (eintr) {
+            send = prev_send + sent;
             continue;
         }