In the installed perl module F77.pm (in the FreeBSD section), the variable $gfortran is set to 'gfortran48'. The default version of gfortran installed on FeŕeeBSD 11 seems to be 6. This causes the next line: $dir = `$gfortran -print-file-name=libgfortran.a`; to return empty. This in turn means that libgfortran is not compiled in when ExtUtils-F77 is used by applications, causing undefined refs.. See bug #225375.
Created attachment 190083 [details] patch to use the default gfortran instead of 4.8 This is to default to the whatever version of gfortran happens to be installed. instead of silently requiring 4.8
A commit references this bug: Author: sunpoet Date: Fri Jan 26 18:13:52 UTC 2018 New revision: 460046 URL: https://svnweb.freebsd.org/changeset/ports/460046 Log: Fix FC substitution - Bump PORTREVISION for package change PR: 225467 Submitted by: Erik B Knudsen <erkn@fysik.dtu.dk> Changes: head/lang/p5-ExtUtils-F77/Makefile
Committed. Thanks!