Fix autogen.sh’s spurious ‘git diff’ output

Problem reported by Gerd Möllmann (Bug#68464).
* .gitignore: Ignore files in exec that are now copied from build-aux.
* admin/merge-gnulib (avoided_flags): Instead of clearing
autom4te.cache here ...
* autogen.sh (do_git): ... clear it here.
Use config.guess, config.sub and install-sh from
the Emacs repository, as they are more likely to be up to date.
This avoids unnecessary differences among different builders,
and avoids unnecessary ‘git diff’ output after autogen.sh.
Also, copy these files from build-aux to exec since there
should be no difference between the two copies.
* exec/config.guess, exec/config.sub, exec/install-sh:
Remove from repository, as autogen.sh now copies them from build-aux.

1 files changed, 16 insertions, 0 deletions

diff --git a/autogen.sh b/autogen.sh
index be41771cae7..f56966ae0d1 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -239,6 +239,16 @@ Please report any problems with this script to bug-gnu-emacs@gnu.org .'
 
   fi                            # do_check
 
+  # Stale caches can confuse autoconf.
+  rm -fr autom4te.cache exec/autom4te.cache || exit
+
+  # In build-aux save config.guess, config.sub and install-sh
+  # in case autoreconf overwrites them, as we rely on the copies
+  # in Git, which are updated by admin/merge-gnulib.
+  for file in config.guess config.sub install-sh; do
+    cp -p build-aux/$file build-aux/$file.tmp || exit
+  done
+
   # Build aclocal.m4 here so that autoreconf need not use aclocal.
   # aclocal is part of Automake and might not be installed, and
   # autoreconf skips aclocal if aclocal.m4 is already supplied.
@@ -269,6 +279,12 @@ Please report any problems with this script to bug-gnu-emacs@gnu.org .'
   # Now, run autoreconf inside the exec directory to generate its
   # configure script.
   autoreconf -fi exec || exit
+
+  # Restore config.guess etc. in build-aux, and copy them to exec.
+  for file in config.guess config.sub install-sh; do
+    cp build-aux/$file.tmp exec/$file &&
+    mv build-aux/$file.tmp build-aux/$file || exit
+  done
 fi