The files: iconv.m4 lib-ld.m4  lib-link.m4  lib-prefix.m4
were obtained from gettext-0.11.4-5 sources.

The file: glib-gettext.m4 was obtained from glib2-devel (go figure!)

They are used in graphviz to avoid requiring gettext be installed.


The file ax_check_compile_flag.m4 was obtained from 
    http://gnu.mirrors.hoobly.com/autoconf-archive/autoconf-archive-2018.03.13.tar.xz
