`expr` is resolved to /bin/expr in FreeBSD, also in Linux emulation layer, but linux_base-c6 only has [/compat/linux]/usr/bin/expr installed, result in the FreeBSD version of `expr` being invoked. Some software breaks. Linking [/compat/linux]/usr/bin/expr to [/compat/linux]/bin/expr solves the problem.
Auto-assigned to maintainer emulation@FreeBSD.org
A commit references this bug: Author: tijl Date: Sun Feb 8 10:34:15 UTC 2015 New revision: 378639 URL: https://svnweb.freebsd.org/changeset/ports/378639 Log: - White space fixes - Like r315899 did for linux_base-f10, add some symlinks to linux_base-c6 for executables that exist in /usr/bin on Linux but /bin on FreeBSD. This guarantees that Linux shell scripts run the Linux executables and not the FreeBSD ones. PR: 197406 Changes: head/emulators/linux_base-c6/Makefile head/emulators/linux_base-c6/pkg-plist