On Thu, 2020-11-05 at 09:25 +0000, Geoff Clare via austin-group-l at
The Open Group wrote:
> > .SUFFIXES:
> > .SUFFIXES: .c .i .o
>
>
> That doesn't make any difference, since .c and .o are both in the
> specified suffixes, so that brings the default .c.o rule into play.
Sorry, I didn't read your example closely enough.
Not only do you have to remove pre-existing suffixes, but you have to
be very careful to order the suffixes correctly when you redefine them.
I find the text in the standard somewhat confusing (particularly how
when first introducing inference rules they are shown as ".s1.s2" but
then a few paragraphs later this is changed to ".s2.s1"; if you miss
that switch then the rest of the text doesn't make any sense).
The order in which suffix rules are found depends on the order in which
the suffixes appear in .SUFFIXES. To make your example work you need
the order to be this:
.SUFFIXES:
.SUFFIXES: .o .i .c
rather than ".c .i .o"... in particular you want the .c suffix to be
after the .i suffix so that rules with .i are preferred.
