meson: import rust module into a global variable

Tested-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

meson.build

@@ -15,6 +15,7 @@ meson.add_postconf_script(find_program('scripts/symlink-install-tree.py'))
 
 not_found = dependency('', required: false)
 keyval = import('keyval')
+rust = import('rust')
 ss = import('sourceset')
 fs = import('fs')
 
@@ -3983,7 +3984,7 @@ if have_rust and have_system
   # this case you must pass the path to `clang` and `libclang` to your build
   # command invocation using the environment variables CLANG_PATH and
   # LIBCLANG_PATH
-  bindings_rs = import('rust').bindgen(
+  bindings_rs = rust.bindgen(
     input: 'rust/wrapper.h',
     dependencies: common_ss.all_dependencies(),
     output: 'bindings.rs',

rust/qemu-api-macros/meson.build

@@ -2,7 +2,7 @@ quote_dep = dependency('quote-1-rs', native: true)
 syn_dep = dependency('syn-2-rs', native: true)
 proc_macro2_dep = dependency('proc-macro2-1-rs', native: true)
 
-_qemu_api_macros_rs = import('rust').proc_macro(
+_qemu_api_macros_rs = rust.proc_macro(
   'qemu_api_macros',
   files('src/lib.rs'),
   override_options: ['rust_std=2021', 'build.rust_std=2021'],