Merge branch 'jc/maint-protect-sh-from-ifs' into maint-1.7.11

When the user exports a non-default IFS without HT, scripts that rely on being able to parse "ls-files -s | while read a b c..." start to fail. Protect them from such a misconfiguration. * jc/maint-protect-sh-from-ifs: sh-setup: protect from exported IFS