Add rename-all=prefix:

This adds a new rename-all annotation which allows setting a specific
prefix to all enum fields. For example:

```rust
/// cbindgen:rename-all=prefix:ERR_
enum Error {
   Bad = 0,
   VeryBad = 1
}
```

While in principle this can be added to the config file, it's primarily
useful for overrides on a case-by-case basis.

src/bindgen/ir/enumeration.rs

@@ -154,7 +154,7 @@ impl EnumVariant {
 
         let body_rule = enum_annotations
             .parse_atom::<RenameRule>("rename-variant-name-fields")
-            .unwrap_or(config.enumeration.rename_variant_name_fields);
+            .unwrap_or(config.enumeration.rename_variant_name_fields.clone());
 
         let body = match variant.fields {
             syn::Fields::Unit => VariantBody::Empty(annotations),
@@ -556,7 +556,7 @@ impl Item for Enum {
         let rules = self
             .annotations
             .parse_atom::<RenameRule>("rename-all")
-            .unwrap_or(config.enumeration.rename_variants);
+            .unwrap_or(config.enumeration.rename_variants.clone());
 
         if let Some(r) = rules.not_none() {
             self.variants = self

src/bindgen/ir/function.rs

@@ -159,7 +159,7 @@ impl Function {
         let rules = self
             .annotations
             .parse_atom::<RenameRule>("rename-all")
-            .unwrap_or(config.function.rename_args);
+            .unwrap_or(config.function.rename_args.clone());
 
         if let Some(r) = rules.not_none() {
             let args = std::mem::take(&mut self.args);

src/bindgen/ir/structure.rs

@@ -342,7 +342,7 @@ impl Item for Struct {
             let field_rules = self
                 .annotations
                 .parse_atom::<RenameRule>("rename-all")
-                .unwrap_or(config.structure.rename_fields);
+                .unwrap_or(config.structure.rename_fields.clone());
 
             if let Some(o) = self.annotations.list("field-names") {
                 for (dest, src) in names.zip(o) {

src/bindgen/ir/union.rs

@@ -171,7 +171,7 @@ impl Item for Union {
         let rules = self
             .annotations
             .parse_atom::<RenameRule>("rename-all")
-            .unwrap_or(config.structure.rename_fields);
+            .unwrap_or(config.structure.rename_fields.clone());
 
         if let Some(o) = self.annotations.list("field-names") {
             let mut overriden_fields = Vec::new();

src/bindgen/mangle.rs

@@ -93,6 +93,7 @@ impl<'a> Mangler<'a> {
                     &self
                         .config
                         .rename_types
+                        .clone()
                         .apply(&sub_path, IdentifierType::Type),
                 );
             }
@@ -101,6 +102,7 @@ impl<'a> Mangler<'a> {
                     &self
                         .config
                         .rename_types
+                        .clone()
                         .apply(primitive.to_repr_rust(), IdentifierType::Type),
                 );
             }

src/bindgen/rename.rs

@@ -28,7 +28,7 @@ impl<'a> IdentifierType<'a> {
 }
 
 /// A rule to apply to an identifier when generating bindings.
-#[derive(Debug, Clone, Copy, Default)]
+#[derive(Debug, Clone, Default)]
 pub enum RenameRule {
     /// Do not apply any renaming. The default.
     #[default]
@@ -50,6 +50,8 @@ pub enum RenameRule {
     /// Converts the identifier to SCREAMING_SNAKE_CASE and prefixes enum variants
     /// with the enum name.
     QualifiedScreamingSnakeCase,
+    /// Adds a given prefix
+    Prefix(String),
 }
 
 impl RenameRule {
@@ -61,7 +63,7 @@ impl RenameRule {
     }
 
     /// Applies the rename rule to a string
-    pub fn apply<'a>(self, text: &'a str, context: IdentifierType) -> Cow<'a, str> {
+    pub fn apply<'a>(&self, text: &'a str, context: IdentifierType) -> Cow<'a, str> {
         use heck::*;
 
         if text.is_empty() {
@@ -90,6 +92,7 @@ impl RenameRule {
                 result.push_str(&RenameRule::ScreamingSnakeCase.apply(text, context));
                 result
             }
+            RenameRule::Prefix(prefix) => prefix.to_owned() + text,
         })
     }
 }
@@ -98,6 +101,9 @@ impl FromStr for RenameRule {
     type Err = String;
 
     fn from_str(s: &str) -> Result<RenameRule, Self::Err> {
+        const PREFIX: &str = "prefix:";
+        const PREFIX_LEN: usize = PREFIX.len();
+
         match s {
             "none" => Ok(RenameRule::None),
             "None" => Ok(RenameRule::None),
@@ -132,6 +138,8 @@ impl FromStr for RenameRule {
             "QualifiedScreamingSnakeCase" => Ok(RenameRule::QualifiedScreamingSnakeCase),
             "qualified_screaming_snake_case" => Ok(RenameRule::QualifiedScreamingSnakeCase),
 
+            s if s.starts_with(PREFIX) => Ok(RenameRule::Prefix(s[PREFIX_LEN..].to_string())),
+
             _ => Err(format!("Unrecognized RenameRule: '{}'.", s)),
         }
     }