Version 2.42.6
- #282 - Fix drop-shadows generated from Inkscape; we were overwriting
  a surface inadvertently.
- #241 - Fix confusion between feSpotLight and feDistantLight (Ivan
  Molodetskikh).
- #292 - Don't panic if we try to clip with an empty region.
- Fix out-of-tree builds and tests (Jehan).
- Compilation can now use a RUST_TARGET variable to override the host
  triplet when cross-compiling.  See COMPILING.md for details (Fabrice
  Fontaine).