Figure out how to set up a font map on Windows
In !830 (merged) I disabled running make check
on the msys2 build, since on Windows rsvg/src/test_utils/mod.rs
does not set up the font map for testing. So, the tests that use PNG reference files and that have text in them all fail.
Find a way to set up an equivalent font map on Windows (text rendering still goes through Cairo/Freetype, right?), or make a way to disable specifically those tests there while enabling the rest of the test suite.