input file ends with non-newline

Arguments are collected if a macro name is "immediately" followed by a
left parenthesis. Experiment shows that arguments are not collected
when a macro name occurs at the end of a file (without a following
newline) and the next input file begins with a left parenthesis. I
believe this behavior is incorrect.

However, the underlying error lies not with m4, but with the input
file. According to POSIX, a valid nonempty text file must end with a
newline. Other experiment suggests that m4 silently appends a missing
newline. Should it not warn when it does so?

Doug