[tlbuild] dvisvgm link errors when building with --with-system-libgs

[Paul Vojta]

On Wed, Mar 15, 2017 at 11:14:22AM -0400, Ken Brown wrote:
> On 3/10/2017 10:22 PM, Paul Vojta wrote:
> >You're right.  It was probably the --disable-native-texlive-build
> >option.  Sorry not to have mentioned that.
> [...]
> >With the patch applied, dvisvgm will successfully build (at least on
> >my system, and probably most others) when --disable-native-texlive-build
> >is used, but it doesn't change anything when --disable-native-texlive-build
> >is not used.  Without the patch, I expect that the dvisvgm build
> >(with --disable-native-texlive-build) will fail on all platforms that have
> >a reasonably recent libgs installed.
> 
> Hi Paul,
> 
> I agree that something like your patch is needed with
> --disable-native-texlive-build and with a recent enough Ghostscript.  My
> only quibble is with this deletion:
> 
> -		LIBS=`echo $LIBS | sed "s/-lgs //" $LIBS`
> 
> That line is relevant when the installed Ghostscript is too old, so I'm not
> sure why you're touching it.

The macros KPSE_SAVE_FLAGS and KPSE_RESTORE_FLAGS save and restore LIBS
and INCLUDES.  So any changes to LIBS between the two are discarded by
KPSE_RESTORE_FLAGS.  So the above line doesn't do anything.  The real
action is what's happening to LIBGS_LIBS (and LIBGS_INCLUDES).
In the case of an old gs version, LIBGS_LIBS remains empty, but it is
set to "-lgs" in the case of a sufficiently recent version of gs.

The value of LIBGS_LIBS is used in texk/dvisvgm/dvisvgm-src/src/Makefile .

Paul