Re: Using Perl's cc

[Eli Zaretskii]

> Date: Sat, 11 Jul 2015 15:23:15 +0100
> From: Gavin Smith <address@hidden>
> Cc: address@hidden
> 
> On 11 July 2015 at 14:10, Eli Zaretskii <address@hidden> wrote:
> > Below is the patch I have come up with.  It still lacks a fully
> > functional wcwidth implementation.  Let me know if you think it's OK
> > to commit these changes in their current form, or factor out the
> > Windows specific code in some way.
> 
> Yes, fine to commit.
> 
> > I can successfully compile the code, but linking it into a shared
> > library fails, see below.
> >
> > Explanation of variables set on the Make command line:
> >
> >   . PERL_INC needs to point to the native Perl's include directory;
> >     hopefully this will eventually done by configure
> 
> configure already sets PERL_INC. What did configure set it to? Do you
> have multiple installations of Perl on your system, and is the right
> one being used by the configure script/fetch_conf.pl?

Yes, like I explained earlier, we need a configure-time option to tell
configure which Perl to invoke for PERL_INC etc.

> >   . -no-undefined -- without this flag, libtool will not build shared
> >     libraries on Windows, because building a shared library on Windows
> >     cannot leave any unresolved references
> 
> Shouldn't libtool provide this flag automatically?

I don't know.  What I see in several other projects I built, they all
manually add -no-undefined in Makefile.am, on all supported platforms,
not just on Windows, probably to avoid another configure-time test.

> >   . -lperl520 and the corresponding -L switch need to be given to
> >     provide the import library for building the shared library, with
> >     symbols that tell the linker how to find functions defined by Perl
> >     itself that the XS extension calls; without that library I have
> >     tons of undefined references
> 
> Is there any way of detecting these flag automatically? For example,
> on my system the configuration values for Perl are in a file
> /usr/lib/perl5/Config_heavy.pl. If you have a file like that on your
> system, you could look to see if "-lperl520" is given anywhere.

Yes, I have such a file; and yes, libperl520.a is mentioned there.
But I see no -lperl520.  Can you tell me how to get Config_heavy.pl to
report some useful values?  Maybe it will spit out the -lperl520
argument as well.