fix #3367: Consolidate extern fn block for fn and static symbols

bindgen-tests/tests/headers/extern-block-attrs-many.h

@@ -0,0 +1,3 @@
+// bindgen-flags: --extern-block-attrs '#[allow(dead_code)]' --extern-block-attrs '#[cfg_attr(not(windows), link(wasm_import_module = "test-module"))]'
+
+void test_function();

bindgen-tests/tests/headers/extern-block-attrs-merge.h

@@ -0,0 +1,6 @@
+// bindgen-flags: --extern-block-attrs '#[allow(dead_code)]' --merge-extern-blocks
+
+void test_function();
+
+extern int test_var;
+extern const int test_const_var;

bindgen-tests/tests/headers/extern-block-attrs-wasm.h

@@ -0,0 +1,3 @@
+// bindgen-flags: --extern-block-attrs '#[allow(dead_code)]' --wasm-import-module-name test-module
+
+void test_function();

bindgen-tests/tests/headers/extern-block-attrs.h

@@ -0,0 +1,6 @@
+// bindgen-flags: --extern-block-attrs '#[allow(dead_code)]'
+
+void test_function();
+
+extern int test_var;
+extern const int test_const_var;

bindgen/codegen/mod.rs

@@ -844,6 +844,20 @@ impl CodeGenerator for Var {
                 }
             });
 
+            let mut block_attributes = quote! {};
+            for attr in &ctx.options().extern_block_attrs {
+                let parsed_attr = proc_macro2::TokenStream::from_str(attr).unwrap_or_else(
+                    |err| {
+                        panic!(
+                            "Error parsing extern static block attribute `{attr}`: {err}"
+                        )
+                    },
+                );
+                block_attributes.extend(quote! {
+                    #parsed_attr
+                });
+            }
+
             let maybe_mut = if self.is_const() {
                 quote! {}
             } else {
@@ -857,6 +871,7 @@ impl CodeGenerator for Var {
                 .then(|| quote!(unsafe));
 
             let tokens = quote!(
+                #block_attributes
                 #safety extern "C" {
                     #(#attrs)*
                     pub static #maybe_mut #canonical_ident: #ty;
@@ -4785,7 +4800,7 @@ impl CodeGenerator for Function {
         }
 
         let mut block_attributes = quote! {};
-        for attr in &ctx.options().extern_fn_block_attrs {
+        for attr in &ctx.options().extern_block_attrs {
             let parsed_attr = proc_macro2::TokenStream::from_str(attr).unwrap_or_else(
                 |err| {
                     panic!(

bindgen/options/cli.rs

@@ -448,9 +448,9 @@ struct BindgenCommand {
     /// The NAME to be used in a #[link(wasm_import_module = ...)] statement
     #[arg(long, value_name = "NAME")]
     wasm_import_module_name: Option<String>,
-    /// Attributes to apply to the extern function block.
+    /// Attributes to apply to extern blocks.
     #[arg(long, value_name = "ATTRS")]
-    extern_fn_block_attrs: Vec<String>,
+    extern_block_attrs: Vec<String>,
     /// Use dynamic loading mode with the given library NAME.
     #[arg(long, value_name = "NAME")]
     dynamic_loading: Option<String>,
@@ -678,7 +678,7 @@ where
         enable_function_attribute_detection,
         use_array_pointers_in_arguments,
         wasm_import_module_name,
-        extern_fn_block_attrs,
+        extern_block_attrs,
         dynamic_loading,
         dynamic_link_require_all,
         prefix_link_name,
@@ -940,7 +940,7 @@ where
             time_phases,
             use_array_pointers_in_arguments => Builder::array_pointers_in_arguments,
             wasm_import_module_name,
-            extern_fn_block_attrs => Builder::extern_fn_block_attrs,
+            extern_block_attrs => Builder::extern_block_attrs,
             ctypes_prefix,
             anon_fields_prefix,
             generate => Builder::with_codegen_config,

bindgen/options/mod.rs

@@ -1917,20 +1917,20 @@ options! {
         as_args: "--use-array-pointers-in-arguments",
     },
     /// Attributes to add to all `extern` blocks.
-    extern_fn_block_attrs: Vec<String> {
+    extern_block_attrs: Vec<String> {
         methods: {
             /// Add an attribute to all the `extern` blocks generated by `bindgen`.
             ///
             /// This can be used to add attributes such as `#[link(...)]` to all
             /// the `extern` blocks.
-            pub fn extern_fn_block_attrs<T: Into<String>>(mut self, attr: T) -> Self {
-                self.options.extern_fn_block_attrs.push(attr.into());
+            pub fn extern_block_attrs<T: Into<String>>(mut self, attr: T) -> Self {
+                self.options.extern_block_attrs.push(attr.into());
                 self
             }
         },
         as_args: |attrs, args| {
             for attr in attrs {
-                args.push("--extern-fn-block-attrs".to_owned());
+                args.push("--extern-block-attrs".to_owned());
                 args.push(attr.clone());
             }
         },
@@ -1946,7 +1946,7 @@ options! {
                 mut self,
                 import_name: T,
             ) -> Self {
-                self.options.extern_fn_block_attrs.push(format!(
+                self.options.extern_block_attrs.push(format!(
                     "#[link(wasm_import_module = \"{}\")]", import_name.into()
                 ));
                 self