dirstate: add test showing dirstate version mismatch causes an error
We should fall back to trying dirstate v1 when v2 fails to read.
# By default Rust will not export dynamic symbols from built executables.
# Python symbols need to be exported from executables in order for that
# executable to load Python extension modules, which are shared libraries.
# Otherwise, the extension module / shared library is unable to resolve
# Python symbols. This file contains target-specific configuration
# overrides to export dynamic symbols from executables.
#
# Ideally we would achieve this functionality via the build.rs build
# script. But custom compiler flags via build scripts apparently only
# support limited options.
[target.x86_64-unknown-linux-gnu]
rustflags = ["-C", "link-args=-Wl,-export-dynamic"]