build: do not repeatedly build some docs

Text versions of manpages do not need to be generated for normal
installations, they're only used for generating HTML and our
amazing, award-winning homepage.

We'll also rely on touch(1) instead of Perl utime to benefit
users w/o git-set-file-times in txt2pre.  Perl numeric values
cannot represent nanosecond resolution accurately even with
Time::HiRes; which causes nanosecond-aware make(1)
implementations to repeatedly rebuild.

1 files changed, 9 insertions, 5 deletions

diff --git a/Documentation/common.perl b/Documentation/common.perl
index 5fdbe8da..3a6617c4 100755
--- a/Documentation/common.perl
+++ b/Documentation/common.perl
@@ -34,11 +34,15 @@ L<http://4uok3hntl7oi7b4uf4rtfwefqeexfzil2w6kgk2jn5z2f764irre7byd.onion/meta/>
                         ^AUTO-GENERATED-SEARCH-TERMS-END\n
                         !search_terms()!emsx;
         $s =~ s/[ \t]+$//sgm;
-        next if $s eq $orig;
-        seek($fh, 0, SEEK_SET) or die "seek: $!";
-        truncate($fh, 0) or die "truncate: $!";
-        print $fh $s or die "print: $!";
-        close $fh or die "close: $!";
+        if ($s eq $orig) {
+                my $t = time;
+                utime($t, $t, $fh);
+        } else {
+                seek($fh, 0, SEEK_SET) or die "seek: $!";
+                truncate($fh, 0) or die "truncate: $!";
+                print $fh $s or die "print: $!";
+                close $fh or die "close: $!";
+        }
 }
 
 sub search_terms {