(This is really in response to Peter Dalgaard, not to myself)
This seems to come from constructions of the form
for i in $FOO : do .... ; done
If $FOO is empty, then the resulting "for i in ;" is a syntax error
with some versions of bash and sh.
Given that one should generally be writing scripts for the Bourne
shell, it is IMHO the case that "for i in ;" is a syntax error,
period.
Current Linux versions of bash do not have that behaviour.
...violating Bourne shell compatibility in yet another way...
One workaround could be to upgrade bash.
If R is to be an application that is not specific to (recent
distributions
of) Linux, one should expect and code for systems that may not have
bash
at all but only the Bourne shell.
Another workaround could be to safeguard the for-loop with
test "$FOO" != "" && for i in $FOO : do .... ; done
in all of the Makefiles where this can be an issue.
That is one of the possible ways in which R developers could, I
suppose, address the issue.