irc-announce: fix more portable cat2

krebs/5pkgs/simple/irc-announce/default.nix

@@ -24,7 +24,12 @@ pkgs.writeDashBin "irc-announce" ''
   # echo2 and cat2 are used output to both, stdout and stderr
   # This is used to see what we send to the irc server. (debug output)
   echo2() { echo "$*"; echo "$*" >&2; }
-  cat2() { (read x ; echo "$x" ; echo "$x" >&2) }
+  cat2() {
+    while read -r line; do
+      echo "$line"
+      echo "$line" >&2
+    done
+  }
 
   # privmsg_cat transforms stdin to a privmsg
   privmsg_cat() { awk '{ print "PRIVMSG "ENVIRON["IRC_CHANNEL"]" :"$0 }'; }