mktables: Silence common build warning

The first time mktables is run on a clean directory, mktables.lst is
non-existent.  Rather than warn on this common occurrence, just assume
it is ok, and continue.  The point of the warning was to point out a
potential problem.  But it occurs so often that people have gotten
inured (habituated) to it, and it has lost all effectiveness.  Better to
not output it, and have any problems show up as repeated rebuilds that
will annoy enough to be dealt with.

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/unicore/mktables b/lib/unicore/mktables
index 77adadbd84..0c10453a00 100644
--- a/lib/unicore/mktables
+++ b/lib/unicore/mktables
@@ -13822,14 +13822,17 @@ File::Find::find({
 
 my @mktables_list_output_files;
 
-if ($write_unchanged_files) {
+if (! -e $file_list) {
+    print "'$file_list' doesn't exist, so forcing rebuild.\n" if $verbosity >= $VERBOSE;
+    $write_unchanged_files = 1;
+} elsif ($write_unchanged_files) {
     print "Not checking file list '$file_list'.\n" if $verbosity >= $VERBOSE;
 }
 else {
     print "Reading file list '$file_list'\n" if $verbosity >= $VERBOSE;
     my $file_handle;
     if (! open $file_handle, "<", $file_list) {
-        Carp::my_carp("Failed to open '$file_list' (this is expected to be missing the first time); turning on -globlist option instead: $!");
+        Carp::my_carp("Failed to open '$file_list'; turning on -globlist option instead: $!");
         $glob_list = 1;
     }
     else {