zlib & sqlite3: pkgconfig support

I’m sure there’s a legitimate reason we haven’t done this before, and
there’s some conversation I’ve missed somewhere, but I’d love to get
this done and be able to stop doing the ZLIB CFLAG/LDFLAG dance so
often. This is a rough draft, I doubt the zlib version is actually
identical for the last 3 OS versions, although it could have been. But
if we can get this done, I’d be super up for it.
aria2: update 1.18.8_1 bottle.
mkvtoolnix: update 7.3.0 bottle.
pdf2htmlex: update 0.12 bottle.
spdylay: update 1.3.1 bottle.