Ignore build commit and build date from build artifacts for proc macros

[sp1ritCS]

I'm running rustc 1.54.0 provided by my distribution (openSUSE Tumbleweed). However, different to the rustc compiled for rustup, running rustc --version just returns

rustc 1.54.0

without any additional (commit builtdate) suffix. However
https://github.com/rust-analyzer/rust-analyzer/blob/b641a66078ce2f2363e9a3b050ba448b93fb7cb6/crates/proc_macro_api/src/version.rs#L41
tries to parse it and thus throws an error on projects using proc macros:

proc-macro /home/admin/workspace/utopia/core/target/debug/deps/libpin_project_internal-626b9b04409c0257.so failed to find the given version. Reason: no commit info
Failed to find proc macros. Error: ExpansionError(
    "Cannot create expander for /home/admin/workspace/utopia/core/target/debug/deps/libpin_project_internal-626b9b04409c0257.so: Io(Custom { kind: InvalidData, error: \"no commit info\" })",
)
proc-macro /home/admin/workspace/utopia/core/target/debug/deps/libserde_derive-06f5854d568d3852.so failed to find the given version. Reason: no commit info
Failed to find proc macros. Error: ExpansionError(
    "Cannot create expander for /home/admin/workspace/utopia/core/target/debug/deps/libserde_derive-06f5854d568d3852.so: Io(Custom { kind: InvalidData, error: \"no commit info\" })",
)
proc-macro /home/admin/workspace/utopia/core/target/debug/deps/libserde_derive-06f5854d568d3852.so failed to find the given version. Reason: no commit info
Failed to find proc macros. Error: ExpansionError(
    "Cannot create expander for /home/admin/workspace/utopia/core/target/debug/deps/libserde_derive-06f5854d568d3852.so: Io(Custom { kind: InvalidData, error: \"no commit info\" })",
)
proc-macro /home/admin/workspace/utopia/core/target/debug/deps/libthiserror_impl-ffd65b6359e21d55.so failed to find the given version. Reason: no commit info
Failed to find proc macros. Error: ExpansionError(
    "Cannot create expander for /home/admin/workspace/utopia/core/arget/debug/deps/libthiserror_impl-ffd65b6359e21d55.so: Io(Custom { kind: InvalidData, error: \"no commit info\" })",
)
proc-macro /home/admin/workspace/utopia/core/target/debug/deps/libtokio_macros-333f39eaae1b9a91.so failed to find the given version. Reason: no commit info
Failed to find proc macros. Error: ExpansionError(
    "Cannot create expander for /home/admin/workspace/utopia/core/target/debug/deps/libtokio_macros-333f39eaae1b9a91.so: Io(Custom { kind: InvalidData, error: \"no commit info\" })",
)
Database loaded:     313.58ms, 168minstr
  crates: 1, mods: 1, decls: 12, fns: 3
Item Collection:     6.77s, 48ginstr
  exprs: 364, ??ty: 18 (4%), ?ty: 19 (5%), !ty: 0
Inference:           2.72s, 18ginstr
Total:               9.49s, 66ginstr

I've attached a fairly simple patch for rust-analyzer that fixes it (at least in my case), by making commit and date optional. Feel free to merge it, if you consider it quality enough.
0001-proc_macro_api-make-commit-date-suffix-of-binary-ver.patch.gz

[lnicola]

What does rustc -vV print? There's another place (debugging) where we use that information.

The commit and date here seem to be unused, currently.

[sp1ritCS]

rustc 1.54.0
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 1.54.0
LLVM version: 12.0.1

the patch I sent makes it work, so that seems to be the only place that happens

[lnicola]

the patch I sent makes it work, so that seems to be the only place that happens

There's another place -- #8624, but I'm not sure how that works, since my toolchain doesn't seem to embed the commit hash in the symbol paths. On the other hand, #9872 implies they are still needed.

Anyway, it seems reasonable to merge your changes. I'll do that a bit later, unless you come up with a PR first.