Don't attempt to check empty fields

externalLinks

@@ -4,8 +4,8 @@
 
 version () {
     echo '$Author: zimoch $' >&2
-    echo '$Date: 2016/10/06 13:26:53 $' >&2
-    echo '$Revision: 1.21 $' >&2
+    echo '$Date: 2018/07/05 15:09:08 $' >&2
+    echo '$Revision: 1.22 $' >&2
     echo '$Source: /cvs/G/EPICS/App/scripts/externalLinks,v $' >&2
     exit 1
 }
@@ -444,6 +444,7 @@ function expandFile () {
         }
         fieldvalue[record,field] = value 
         definition[record,field] = filename ":" line
+        if (value == "") next
         if (!isfield[rtype,field]) {
             printf("%s:%d\n\t%s record \"%s\" unknown field %s\n\tshould be one of:\n%s\n\n",
                 filename, line, rtype, record, field, fields[rtype]) > "/dev/stderr"