Regenerate autotools output with autotools 1.14.1

Running `./configure` generated by autotools 1.11.1 caused the following
failure on an up-to-date Arch:

    sed: can't read config/ltmain.sh: No such file or directory
    sed: can't read config/ltmain.sh: No such file or directory
    mv: cannot stat 'libtoolT': No such file or directory
    cp: cannot stat 'libtoolT': No such file or directory
    chmod: cannot access 'libtool': No such file or directory