[tlbuild] Missing includes for zlib when building woff2 (dvisvgm)

[Mojca Miklavec]

Dear Karl & Martin,

This is not critical to be fixed for TL 2019, but I wanted to report
it and it would be nice to fix it for the future.

I was playing a bit more with the MinGW-w64 cross-compiler, using the
following flags (suggested by Luigi, but I added --disable-xetex since
that one requires some more tweaking to get fontconfig working):

--without-x --enable-multiplatform --disable-xpdfopen --enable-shared
--disable-xetex --disable-native-texlive-build

(I can provide full script if needed.)

However this fails when building dvisvgm's built-in dependency woff2.
When configuring dvisvgm itself the zlib is found and the flags seem
to be there, but they don't seem to propagate all the way down to
woff2.

I'm not exactly sure how to make a standalone bug report to dvisvgm as
that would require somehow replicating the external zlib inclusion.
The makefile seems simple enough though, so I guess that this should
be "fixable". (My blind guess is that we usually don't notice this
because any given system probably has zlib headers installed. I didn't
try to confirm that yet, I would need some more time and play a bit
more to fix this.)


Compilation on msys2 is still broken due to some ICU naming issues (I
thought these were supposed to be solved by your / Luigi's patches,
apparently there are still some issues left though).

g++.exe: error: /path/to/Work/libs/icu/icu-build/lib/libicudata.a: No
such file or directory

Mojca