Re: ignore specific file in VPATH/vpath

[Paul Smith]

On Wed, 2018-05-09 at 14:30 +0200, Jannick wrote:
> Separately, an additional note: make's YACC built-in recipe
> 
> %.c: %.y
> #  recipe to execute (built-in):
>         $(YACC.y) $< 
>          mv -f y.tab.c $@
> 
> appears to assume that YACC/bison's output file name defaults to y.tab.c.
> However, it is $*.tab.c for bison >= 3.0 (at least).

Can you tell us what your makefile is using for a "yacc" command?

The default in GNU make is:

  YACC = yacc

and this default, and the behavior of the rules for generating source
and object files using yacc, is required by the POSIX specification for
GNU make: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/make.html

Are you overriding this value to set it to "bison" instead in your
makefile?  Or, does your system actually provide a "yacc" command?

The "yacc" command is defined by POSIX including its generated output
file names: http://pubs.opengroup.org/onlinepubs/009604599/utilities/yacc.html

Basically it's up to you to either (a) use a standard-conforming "yacc"
command, or (b) modify the YACC variable so that it contains a
standard-conforming yacc command, or (c) rewrite the rule to use a
different yacc command.

If your system provides a "yacc" command (option (a)) and it does not
conform to POSIX (generates the wrong output) then that's a bug in your
OS or distribution and you should report that to them.

If you want to follow option (b) above and replace "yacc" with "bison",
then instead of using:

  YACC = bison

you need to use:

  YACC = bison -y

which tells Bison to use traditional output file naming.

Or of course you can use option (c), as you've done, and rewrite the
rule to use whatever output you like.