+esac
+
+# Now exit if we have it, but it failed. Also exit now if we
+# don't have it and --version was passed (most likely to detect
+# the program).
+case "$1" in
+ lex|yacc)
+ # Not GNU programs, they don't have --version.
+ ;;
+
+ tar)
+ if test -n "$run"; then
+ echo 1>&2 "ERROR: \`tar' requires --run"
+ exit 1
+ elif test "x$2" = "x--version" || test "x$2" = "x--help"; then
+ exit 1
+ fi
+ ;;
+
+ *)
+ if test -z "$run" && ($1 --version) > /dev/null 2>&1; then
+ # We have it, but it failed.
+ exit 1
+ elif test "x$2" = "x--version" || test "x$2" = "x--help"; then
+ # Could not run --version or --help. This is probably someone
+ # running `$TOOL --version' or `$TOOL --help' to check whether
+ # $TOOL exists and not knowing $TOOL uses missing.
+ exit 1
+ fi
+ ;;
+esac
+
+# If it does not exist, or fails to run (possibly an outdated version),
+# try to emulate it.
+case "$1" in
+ aclocal*)