meson/rust: wrap bindgens wrap-static-fns functionality

This way the `rust.bindgen` can generate a second output being a C file,
which contains wrapper functions for static inline ones.

This output file can then be compiled via C targets.

docs/markdown/Rust-module.md

@@ -57,6 +57,10 @@ It takes the following keyword arguments
 - `input`: a list of Files, Strings, or CustomTargets. The first element is
   the header bindgen will parse, additional elements are dependencies.
 - `output`: the name of the output rust file
+- `output_inline_wrapper`: the name of the optional output c file containing
+  wrappers for static inline function. Setting this will instruct `bindgen` to
+  generate it by adding the relevant arguments to `args`. This requires
+  `bindgen` `0.64` or newer (*since 1.3.0*).
 - `include_directories`: A list of `include_directories` or `string` objects,
   these are passed to clang as `-I` arguments *(string since 1.0.0)*
 - `c_args`: a list of string arguments to pass to clang untouched

mesonbuild/modules/rust.py

@@ -191,6 +191,12 @@ def test(self, state: ModuleState, args: T.Tuple[str, BuildTarget], kwargs: Func
         ),
         INCLUDE_DIRECTORIES.evolve(since_values={ContainerTypeInfo(list, str): '1.0.0'}),
         OUTPUT_KW,
+        KwargInfo(
+            'output_inline_wrapper',
+            str,
+            default='',
+            since='1.3.0',
+        ),
         DEPENDENCIES_KW.evolve(since='1.0.0'),
     )
     def bindgen(self, state: ModuleState, args: T.List, kwargs: FuncBindgen) -> ModuleReturnValue:
@@ -243,12 +249,22 @@ def bindgen(self, state: ModuleState, args: T.List, kwargs: FuncBindgen) -> Modu
         else:
             name = header.get_outputs()[0]
 
+        inline_wrapper_args = []
+        outputs = [kwargs['output']]
+        if kwargs['output_inline_wrapper']:
+            outputs.append(kwargs['output_inline_wrapper'])
+            inline_wrapper_args = [
+                '--experimental', '--wrap-static-fns',
+                '--wrap-static-fns-path', os.path.join(state.environment.build_dir, state.subdir, kwargs['output_inline_wrapper'])
+            ]
+
         cmd = self._bindgen_bin.get_command() + \
             [
                 '@INPUT@', '--output',
-                os.path.join(state.environment.build_dir, '@OUTPUT@')
+                os.path.join(state.environment.build_dir, '@OUTPUT0@')
             ] + \
-            kwargs['args'] + ['--'] + kwargs['c_args'] + clang_args + \
+            kwargs['args'] + inline_wrapper_args + ['--'] + \
+            kwargs['c_args'] + clang_args + \
             ['-MD', '-MQ', '@INPUT@', '-MF', '@DEPFILE@']
 
         target = CustomTarget(
@@ -258,15 +274,15 @@ def bindgen(self, state: ModuleState, args: T.List, kwargs: FuncBindgen) -> Modu
             state.environment,
             cmd,
             [header],
-            [kwargs['output']],
+            outputs,
             depfile='@[email protected]',
             extra_depends=depends,
             depend_files=depend_files,
             backend=state.backend,
             description='Generating bindings for Rust {}',
         )
 
-        return ModuleReturnValue([target], [target])
+        return ModuleReturnValue(target, [target])
 
 
 def initialize(interp: Interpreter) -> RustModule: