restricted c header imports

compiler/types/types.odin

@@ -59,6 +59,7 @@ Kind :: enum u8 {
 	Slice,
 	Optional,
 	Named,
+	Alias,
 	Struct,
 }
 
@@ -132,7 +133,7 @@ intern :: proc(store: ^Store, candidate: Node) -> Type {
 named :: proc(store: ^Store, pkg, name: u32, qualifier: u32 = 0, file: u32 = 0xffff_ffff) -> Type {
 	normalized_file := file if qualifier != 0 else u32(0)
 	for existing, index in store.nodes {
-		if (existing.kind == .Named || existing.kind == .Struct) &&
+		if (existing.kind == .Named || existing.kind == .Alias || existing.kind == .Struct) &&
 		   existing.pkg == pkg && existing.name == name && existing.qualifier == qualifier &&
 		   existing.file == normalized_file {
 			return DYNAMIC_START+Type(index)
@@ -143,7 +144,7 @@ named :: proc(store: ^Store, pkg, name: u32, qualifier: u32 = 0, file: u32 = 0xf
 
 find_named :: proc(store: ^Store, pkg, name: u32, qualifier: u32 = 0) -> Type {
 	for existing, index in store.nodes {
-		if (existing.kind == .Named || existing.kind == .Struct) &&
+		if (existing.kind == .Named || existing.kind == .Alias || existing.kind == .Struct) &&
 		   existing.pkg == pkg && existing.name == name && existing.qualifier == qualifier {
 			return DYNAMIC_START+Type(index)
 		}
@@ -151,6 +152,18 @@ find_named :: proc(store: ^Store, pkg, name: u32, qualifier: u32 = 0) -> Type {
 	return INVALID
 }
 
+define_alias :: proc(store: ^Store, id, child: Type) -> bool {
+	existing, ok := node(store, id)
+	if !ok || existing.kind != .Named || existing.declared {
+		return false
+	}
+	index := int(id-DYNAMIC_START)
+	store.nodes[index].kind = .Alias
+	store.nodes[index].child = child
+	store.nodes[index].declared = true
+	return true
+}
+
 define_struct :: proc(store: ^Store, id: Type, fields: []Field, c_layout, opaque: bool) -> bool {
 	existing, ok := node(store, id)
 	if !ok || (existing.kind != .Named && existing.kind != .Struct) || existing.declared {