moving submodule external/fox to PR number-6 of fox repository
PR number-6 in fox repo adds a small fix to the autoconf system for ppc64le, that was already pplied to the tarball but missing from the repository (my blame)
This MR updates the commit of the submodule
To be merged rebased on MR !1741 (merged) and re-tested.
Edited by Pietro Delugas