setup file has a problem with /bin/sh on fedora 28 which has bash version 4.4.23
in the env described in subject line, I get:
/home/ron/work/upsPrj/erupt/ups ron@ronlap77 :^) /bin/sh sh-4.4$ . /p/setup sh: `source': is a special builtin sh: unsetenv_: command not found sh-4.4$
I have checked in a change to setup that defines s_source functions for both sh and csh shell (as Marc does in setups).