subprojects: add attrs crate

The attrs crate is a simple combinator-based for Rust attributes.  It
will be used instead of a handwritten parser.

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

rust/meson.build

@@ -13,10 +13,12 @@ libc_rs = dependency('libc-0.2-rs')
 subproject('proc-macro2-1-rs', required: true)
 subproject('quote-1-rs', required: true)
 subproject('syn-2-rs', required: true)
+subproject('attrs-0.2-rs', required: true)
 
 quote_rs_native = dependency('quote-1-rs', native: true)
 syn_rs_native = dependency('syn-2-rs', native: true)
 proc_macro2_rs_native = dependency('proc-macro2-1-rs', native: true)
+attrs_rs_native = dependency('attrs-0.2-rs', native: true)
 
 genrs = []
 

rust/qemu-macros/Cargo.toml

@@ -16,6 +16,7 @@ rust-version.workspace = true
 proc-macro = true
 
 [dependencies]
+attrs = "0.2.9"
 proc-macro2 = "1"
 quote = "1"
 syn = { version = "2", features = ["extra-traits"] }

rust/qemu-macros/meson.build

@@ -8,6 +8,7 @@ _qemu_macros_rs = rust.proc_macro(
     '--cfg', 'feature="proc-macro"',
   ],
   dependencies: [
+    attrs_rs_native,
     proc_macro2_rs_native,
     quote_rs_native,
     syn_rs_native,