Ignore duplicated undocumented things

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Paul Yang <yang.yang@baishancloud.com>
(Merged from https://github.com/openssl/openssl/pull/7423)

util/find-doc-nits

@@ -35,7 +35,7 @@ Find small errors (nits) in documentation.  Options:
     -l Print bogus links
     -n Print nits in POD pages
     -p Warn if non-public name documented (implies -n)
-    -u List undocumented functions
+    -u Count undocumented functions
     -h Print this help message
     -c List undocumented commands and options
 EOF
@@ -270,6 +270,7 @@ my %docced;
 sub checkmacros()
 {
     my $count = 0;
+    my %seen;
 
     print "# Checking macros (approximate)\n";
     foreach my $f ( glob('include/openssl/*.h') ) {
@@ -281,7 +282,7 @@ sub checkmacros()
         while ( <IN> ) {
             next unless /^#\s*define\s*(\S+)\(/;
             my $macro = $1;
-            next if $docced{$macro};
+            next if $docced{$macro} || defined $seen{$macro};
             next if $macro =~ /i2d_/
                 || $macro =~ /d2i_/
                 || $macro =~ /DEPRECATEDIN/
@@ -289,6 +290,7 @@ sub checkmacros()
                 || $macro =~ /DECLARE_/;
             print "$f:$macro\n" if $opt_d;
             $count++;
+            $seen{$macro} = 1;
         }
         close(IN);
     }
@@ -300,15 +302,17 @@ sub printem()
     my $libname = shift;
     my $numfile = shift;
     my $count = 0;
+    my %seen;
 
     foreach my $func ( &parsenum($numfile) ) {
-        next if $docced{$func};
+        next if $docced{$func} || defined $seen{$func};
 
         # Skip ASN1 utilities
         next if $func =~ /^ASN1_/;
 
         print "$libname:$func\n" if $opt_d;
         $count++;
+        $seen{$func} = 1;
     }
     print "# Found $count missing from $numfile\n\n";
 }