Re: parse-datetime: Add support for VPATH builds with OpenBSD 'make'

[Bruno Haible]

I wrote:
> This patch should fix it. Based on
> https://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=commitdiff;h=bf9412ab2e5878f2b64c8ba5d496d7a26ac4d374
> 
> 
> 2024-06-11  Bruno Haible  <bruno@clisp.org>
> 
>       parse-datetime: Add support for VPATH builds with OpenBSD 'make'.
>       * modules/parse-datetime (Makefile.am): Prefix the target file name
>       with '$(srcdir)/'.

It did not fix it. The problem here is that OpenBSD make insists in applying
the Automake .y.c rule, regardless whether I prefix also the dependency with
'$(srcdir)/' or not. And this Automake rule not only is broken; it also
fails because 'bison' is not present.


2024-06-11  Bruno Haible  <bruno@clisp.org>

        parse-datetime: Revert last commit.
        * modules/parse-datetime (Makefile.am): Remove the '$(srcdir)/' prefix
        from the target. Add a comment.

diff --git a/modules/parse-datetime b/modules/parse-datetime
index a49d3667dd..06c6f6173e 100644
--- a/modules/parse-datetime
+++ b/modules/parse-datetime
@@ -46,7 +46,10 @@ Makefile.am:
 # Additionally, here we assume GNU Bison and therefore don't need the ylwrap
 # script.
 # Therefore we override this rule.
-$(srcdir)/parse-datetime.c: parse-datetime.y
+# Unfortunately, overriding the Automake generated .y.c rule does not work in
+# VPATH builds with OpenBSD make. Therefore, for VPATH builds on OpenBSD, the
+# user will need GNU make.
+parse-datetime.c: parse-datetime.y
        $(AM_V_YACC)$(PARSE_DATETIME_BISON) $(YFLAGS) $(AM_YFLAGS) 
$(srcdir)/parse-datetime.y \
        && test ':' = '$(PARSE_DATETIME_BISON)' || { \
          sed -e 's|".*/parse-datetime\.y"|"parse-datetime.y"|' \