libxml2 update requires a kludge

[thomas]

Not only that libxml2 seemed to have dumped http://xmlsoft.org/sources as primary repo [old/new], also it did perform the the switch to cmake. Effect of this is the dropping of the static /usr/lib/libxml2.a, plus a change in the symlink structure for the so's.

Namely the symlink '/usr/lib/libxml2.so.2 -> libxml2.so.2.9.XY', has vanished.
My proposal would be to create it in the postinstall stage, albeit I fear that this will stick around for a long, long time :/

[old] http://xmlsoft.org/sources/libxml2-${PKGVERSION}.tar.gz
[new] https://gitlab.gnome.org/GNOME/libxml2/-/archive/v2.9.13/libxml2-v2.9.13.tar.gz

[thomas]

And it gets worse, the usage of -Wl,-soname,libxml2.so.2.9.13 would yield to a libxml zoo in the future.