(autoreconf): Don't age aclocal.m4's input

files to be 1 second older; just set them to be the same time.
Also, sleep 1 second after the first aclocal, to work around
problems with sub-second time stamps on the input files.

diff --git a/bin/autoreconf.in b/bin/autoreconf.in
index 9f990e8db81ca00485eb204d35981339b1acef86..3cbcab69d1400edc771af6b21cd6ad7fe507c974 100644 (file)
--- a/bin/autoreconf.in
+++ b/bin/autoreconf.in
@@ -288,6 +288,16 @@ sub autoreconf ($)
     }
   else
     {
+      # Some filesystems have sub-second time stamps, and if so we may
+      # run into trouble later, after we rerun autoconf and set the
+      # time stamps of input files to be no greater than aclocal.m4,
+      # because the time-stamp-setting operation (utime) has a
+      # resolution of only 1 second.  Work around the problem by
+      # ensuring that there is at least a one-second window before the
+      # time stamp of aclocal.m4t in which no file time stamps can
+      # fall.
+      sleep 1;
+
       xsystem ("$aclocal $aclocal_flags --output=aclocal.m4t");
       # aclocal may produce no output.
       update_file ('aclocal.m4t', 'aclocal.m4')
@@ -449,7 +459,7 @@ sub autoreconf ($)
              # aclocal.m4.
              #
              # Why is not always the case?  Because we already run
-             # aclocal a first (before tracing), which, for instance,
+             # aclocal at first (before tracing), which, for instance,
              # can find Gettext's macros in .../share/aclocal, so we
              # may have had the right aclocal.m4 already.  Then
              # gettextize is run, and installs locally these M4
@@ -457,11 +467,11 @@ sub autoreconf ($)
              # the _same_ aclocal.m4, and doesn't change its
              # timestamp.  But later, Automake's Makefile expresses
              # that aclocal.m4 depends on these local files, which
-             # are younger, so it triggers aclocal again.
+             # are newer, so it triggers aclocal again.
              #
-             # To make sure aclocal.m4 is younger, we change the
+             # To make sure aclocal.m4 is no older, we change the
              # modification times of the local M4 files to be
-             # slightly older than it.
+             # not newer than it.
              #
              # First, where are the local files?
              my $aclocal_local_dir = '.';
@@ -469,16 +479,15 @@ sub autoreconf ($)
                {
                  $aclocal_local_dir = $1;
                }
-             # All the local files younger than aclocal.m4 are to be
-             # grown older than it.
+             # All the local files newer than aclocal.m4 are to be
+             # made not newer than it.
              my $aclocal_m4_mtime = mtime ('aclocal.m4');
              for my $file (glob ("$aclocal_local_dir/*.m4"), 'acinclude.m4')
                {
-                 if (mtime ($file) >= $aclocal_m4_mtime)
+                 if ($aclocal_m4_mtime < mtime ($file))
                    {
-                     debug "making $file younger than aclocal.m4";
-                     utime $aclocal_m4_mtime - 1, $aclocal_m4_mtime - 1,
-                       $file;
+                     debug "aging $file to be not newer than aclocal.m4";
+                     utime $aclocal_m4_mtime, $aclocal_m4_mtime, $file;
                    }
                }
            }