rust: add utility procedural macro crate

This commit adds a helper crate library, qemu-api-macros for derive (and
other procedural) macros to be used along qemu-api.

It needs to be a separate library because in Rust, procedural macros, or
macros that can generate arbitrary code, need to be special separate
compilation units.

Only one macro is introduced in this patch, #[derive(Object)]. It
generates a constructor to register a QOM TypeInfo on init and it must
be used on types that implement qemu_api::definitions::ObjectImpl trait.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Link: https://lore.kernel.org/r/dd645642406a6dc2060c6f3f17db2bc77ed67b59.1727961605.git.manos.pitsidianakis@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/subprojects/packagefiles/proc-macro2-1-rs/meson.build b/subprojects/packagefiles/proc-macro2-1-rs/meson.build
new file mode 100644
index 0000000000..818ec59336
--- /dev/null
+++ b/subprojects/packagefiles/proc-macro2-1-rs/meson.build
@@ -0,0 +1,31 @@
+project('proc-macro2-1-rs', 'rust',
+  version: '1.0.84',
+  license: 'MIT OR Apache-2.0',
+  default_options: [])
+
+subproject('unicode-ident-1-rs', required: true)
+
+unicode_ident_dep = dependency('unicode-ident-1-rs', native: true)
+
+_proc_macro2_rs = static_library(
+  'proc_macro2',
+  files('src/lib.rs'),
+  gnu_symbol_visibility: 'hidden',
+  override_options: ['rust_std=2021', 'build.rust_std=2021'],
+  rust_abi: 'rust',
+  rust_args: [
+    '--cfg', 'feature="proc-macro"',
+    '--cfg', 'span_locations',
+    '--cfg', 'wrap_proc_macro',
+  ],
+  dependencies: [
+    unicode_ident_dep,
+  ],
+  native: true,
+)
+
+proc_macro2_dep = declare_dependency(
+  link_with: _proc_macro2_rs,
+)
+
+meson.override_dependency('proc-macro2-1-rs', proc_macro2_dep, native: true)