Paul Eggert wrote:
I'm surprised the problem ever went away, as the subtle quoting differences between
It didn't. I was misled by a change to the way that Autoconf picks a shell.
Unless someone else pipes up with the real answer then I suppose we'll have to get to the bottom of this ourselves.
I have already done a good deal of additional debugging since posting the original email. It turns out that the problem is that Autoconf CVS now chooses to use the older factory-supplied NextStep shell, rather than the newer, modern version of Bash which I have installed. Autoconf versions up to 2.59 correctly choose the newer shell.
The reason that Autoconf CVS chooses the older shell is because it is only looking for a shell which implements shell functions (which the NextStep shell does), and the factory-supplied shell is the first one it finds. The reason that 2.59 (and earlier) chooses the newer Bash is that it is looking for a shell which implements $LINENO (which the NextStep shell does _not_). Therefore, 2.59 prefers Bash (since it implements $LINENO) over the factory-supplied NextStep shell.
I think the appropriate fix is to prefer a shell which implements both functions and $LINENO if such a shell can be found. If not, then it should pick a shell which implements one or the other. I am planning on submitting a patch which will implement this heuristic. Not only will this make me happy (since running modern-day configure scripts is impossibly and painfully slow with the old NextStep shell), but it also just seems like the correct approach (i.e. preferring a more functional, modern shell over a less functional, slower one).
-- ES
