Comment 0 for bug 1841191

Upstream issue: https://github.com/rust-lang/cargo/issues/7147

This breaks firefox and thunderbird builds in eoan:

    export CARGO_HOME=/<<BUILDDIR>>/thunderbird-68.0+build4/third_party/cbindgen/.cargo; \
    cargo install --path . --bin cbindgen --root ../../cbindgen
    error: failed to acquire package cache lock

    Caused by:
      failed to open: /sbuild-nonexistent/.cargo/.package-cache

    Caused by:
      Permission denied (os error 13)

The following commit needs to be backported as a distro patch: https://github.com/rust-lang/cargo/commit/2b21fa68368f13b43f4c34886116df2e1b9d276e

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: cargo (not installed)
ProcVersionSignature: Ubuntu 5.0.0-25.26-generic 5.0.18
Uname: Linux 5.0.0-25-generic x86_64
ApportVersion: 2.20.11-0ubuntu7
Architecture: amd64
Date: Fri Aug 23 14:24:46 2019
SourcePackage: cargo
UpgradeStatus: No upgrade log present (probably fresh install)