There's no reason to create this file if none of the serial configure
options are passed.
* configure.ac: Only create serdep.tmp if needed
# These force 'configure's to be done one at a time, to avoid problems
# with contention over a shared config.cache.
rm -f serdep.tmp
+if test "x${enable_serial_build_configure}" = xyes || test "x${enable_serial_host_configure}" = xyes || test "x${enable_serial_target_configure}" = xyes; then
echo '# serdep.tmp' > serdep.tmp
+fi
olditem=
test "x${enable_serial_build_configure}" = xyes &&
for item in ${build_configdirs} ; do