Offline builds with cargo vendor are broken

[jschwe]

The update to Spidermonkey 128 vendored two new crates:

• mozjs_sys/mozjs/intl/icu_capi
• mozjs-sys/mozjs/intl/icu_segmenter_data

cargo vendor places these crates in the top-level vendor directory, leaving the location the mozjs-sys crate empty and causing the build (when forcing build from source or offline build) to fail with:

  Path specified in LOCAL_INCLUDES does not exist: /intl/icu_capi/c/include (resolved to /Users/jschwender/Dev/servo/vendor/mozjs_sys/mozjs/intl/icu_capi/c/include)

[sagudev]

Hm, those files shouldn't be moved when vendoring as we do not use those crates in tree:

mozjs/mozjs-sys/Cargo.toml

Line 38 in f68e385

icu_capi = "1.4.0" # keep in sync with intl/icu_capi/Cargo.toml

(maybe cargo still picks them up due to existence of Cargo.toml, so removing them could fix this). Although it would be more right to patch SM to use headers from our intl_capi crate instead of one provided in tree.