Add #include directives with headers for static wrappers

CHANGELOG.md

@@ -166,6 +166,9 @@
 ## Changed
  * Static functions with no arguments use `void` as their single argument
    instead of having no arguments when the `--wrap-static-fns` flag is used.
+ * The source file generated when the `--wrap-static-fns` flag is enabled now
+   contains `#include` directives with all the input headers and all the source
+   code added with the `header_contents` method.
 ## Removed
  * The following deprecated flags were removed: `--use-msvc-mangling`,
    `--rustfmt-bindings` and `--size_t-is-usize`.

bindgen-integration/build.rs

@@ -242,8 +242,6 @@ fn setup_wrap_static_fns_test() {
         .arg("-o")
         .arg(&obj_path)
         .arg(out_path.join("wrap_static_fns.c"))
-        .arg("-include")
-        .arg(input_header_file_path)
         .output()
         .expect("`clang` command error");
     if !clang_output.status.success() {

bindgen-tests/tests/expectations/tests/generated/wrap_static_fns.c

@@ -1,3 +1,7 @@
+#include "tests/headers/wrap-static-fns.h"
+
+// Static wrappers
+
 int foo__extern(void) asm("foo__extern");
 int foo__extern(void) { return foo(); }
 int bar__extern(void) asm("bar__extern");

bindgen/codegen/mod.rs

@@ -4545,6 +4545,7 @@ pub(crate) mod utils {
     use crate::ir::ty::TypeKind;
     use crate::{args_are_cpp, file_is_cpp};
     use std::borrow::Cow;
+    use std::io::Write;
     use std::mem;
     use std::path::PathBuf;
     use std::str::FromStr;
@@ -4583,6 +4584,24 @@ pub(crate) mod utils {
 
         let mut code = Vec::new();
 
+        if !context.options().input_headers.is_empty() {
+            for header in &context.options().input_headers {
+                writeln!(code, "#include \"{}\"", header)?;
+            }
+
+            writeln!(code)?;
+        }
+
+        if !context.options().input_header_contents.is_empty() {
+            for (name, contents) in &context.options().input_header_contents {
+                writeln!(code, "// {}\n{}", name, contents)?;
+            }
+
+            writeln!(code)?;
+        }
+
+        writeln!(code, "// Static wrappers\n")?;
+
         for &id in &result.items_to_serialize {
             let item = context.resolve_item(id);
             item.serialize(context, (), &mut vec![], &mut code)?;