Re: Libtool head: standalone.at test should use $(CFLAGS)

[Ralf Wildenhues]

Hi Peter,

* Peter Ekberg wrote on Thu, Aug 25, 2005 at 11:05:40AM CEST:
> 
> I discovered a linking problem in the testsuite with my MSVC
> patch, and have found the attached solution...
> 
> 2005-08-25  Peter Ekberg  <address@hidden>
> 
>       * tests/standalone.at: (without autotools): Add
>       $(CFLAGS) to LTCOMPILE and LTLINK.

OK, but I see the need for even more changes: we want $(INCLUDES)
earlier, and we want --tag=CC as well, similar to what Autoconf emits:

LTCOMPILE = $(LIBTOOL) --tag=CC $(LIBTOOLFLAGS) --mode=compile \
        $(CC) $(INCLUDES) $(CPPFLAGS) $(CFLAGS)

> Also, another comment on this test, regarding the following
> exchange from the past between me and Ralf:
> 
> P: So, the only way to use -TP and -TC is to always compile first
> P: (with -c switch) and then link. I think libtool always does it
> P: this way so that may not be a problem?
> 
> R: Yes, libtool requires separated modes for compilation and
> R: linking.

Ouch.  I hope I did not lie there.. (looks at documentation again)
nope, we don't document
  libtool --mode=link $CC -o a.out source.c
and while it may happen to work by chance, I don't think it'll work
in all cases.

I've thought about -TP/-TC again, by the way.  It's basically a very
similar problem as with the different Fortran dialects, so the Right
Fix[tm] would be to add macros to Autoconf to find out whether -Tp
(yes, -Tp not -TP) is necessary, and then use that in a variable
$(CXXFLAGS_cc) or so.  Automake then needs the same adjustment that it
also still needs for $(FC).  Any volunteers?  :)

> Isn't the following Makefile snippet from tests/standalone.at
> in violation, as it compiles main.c and links ltdldemo in one
> go?

I believe so.  Could you be bothered to produce a fix?

> ltdldemo: $(LIBTOOL) module.la libltdl/libltdlc.la main.c
>       $(LTLINK) -o ltdldemo main.c -dlopen module.la
> ./libltdl/libltdlc.la

Thanks,
Ralf