rust: add rust.workspace() skeleton implementation

rust.workspace() is the entry point for global feature resolution.
It loads a Cargo.toml file and ensures that all dependencies will be
built with the correct set of features.

Fixes: #13404
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/test cases/rust/32 rust.workspace workspace/subprojects/answer-2.1/src/lib.rs b/test cases/rust/32 rust.workspace workspace/subprojects/answer-2.1/src/lib.rs
new file mode 100644
index 000000000..b7a721b05
--- /dev/null
+++ b/test cases/rust/32 rust.workspace workspace/subprojects/answer-2.1/src/lib.rs
@@ -0,0 +1,10 @@
+pub fn answer() -> u8
+{
+    42
+}
+
+#[cfg(feature = "large")]
+pub fn large_answer() -> u64
+{
+    42
+}