[Swan-dev] missing bison masked by new Makefiles?

[D. Hugh Redelmeier]

| From: Andrew Cagney <andrew.cagney at gmail.com>

|   I've since
| tweaked it to do an explicit "set -e" (a GNU Make feature is to not
| invoke /bin/sh with "-e").

In general, I'm a big fan of "set -eu" in scripts.  If I were not
lazy, I'd have tried harder to implement that.

Any reason not to use "set -eu" instead of "set -e"?

I admit that shell scripts generated by make rarely need -u since it
is so hard to get a shell variable reference past make.

On a related topic, GNU Make has --warn-undefined-variables.  I don't
know how much pain it would be to adopt that but it would surely
result in more robust makefiles.  (We discussed this slightly on this list 
on Jan 21.)