CHANGES: add a fix backported to 4.99. [skip ci]

Author: guyharris

CHANGES

@@ -113,6 +113,8 @@ DayOfTheWeek, Month DD, YYYY / The Tcpdump Group
       For PCAP_ERROR_CAPTURE_NOTSUP, show the error message provided
         by libpcap for that error if it's non-empty.
       Update the -z option processing. Print "invalid option -- z" when it is.
+    Other:
+      Avoid race condition when receiving signal during shutdown.
     Source code:
       Fix '-tt' option printing when time > 2106-02-07T06:28:15Z.
       Add sub-second packet timestamp checks for invalid micro/nano.