Build failure due to conflicting config.h files for mflua

[Karl Berry]

Hi Daniel - thanks for the report and all the details. I think
HAVE_CONFIG_H is pretty universally defined, since it's a consequence of
TL using automake, so I'm not sure why this is not failing for everyone.

Be that as it may, it seems to me that potrace/config.h should not be
committed at all. Its two non-admin lines are
#define VERSION "1.16"
#define HAVE_INTTYPES_H 1

Leaving VERSION aside, HAVE_INTTYPES_H is only known at configure time,
and varies depends on the local system.  So it is just wrong to have
that defined in the source tree.

Instead, it should be generated by configure and written into the build
tree, like Work/texk/web2c/web2c/w2c/config.h and plenty more. Then it
will be found first, via the "-I.", I believe.

Luigi?

FWIW, regarding w2c/config.h, looking at it now, it would be cleaner for
everything that includes it to explicitly say #include <w2c/config.h>,
as there are config.h files everywhere.  Unfortunately I don't know when
I'll have the energy to look into that.

Also, regarding Makefile.in, of course it is generated from Makefile.am,
so it can't be edited (in TL). As it happens, there was some recent
discussion on the automake list related to the ordering of CPPFLAGS, but
I don't know what the outcome of that will be.

Thanks again for the report,
Karl