Move writing includes to write.rs
diff --git a/gen/src/write.rs b/gen/src/write.rs
index 0514554..9a1331e 100644
--- a/gen/src/write.rs
+++ b/gen/src/write.rs
@@ -1,11 +1,12 @@
+use crate::gen::include::{self, Includes};
 use crate::gen::namespace_organizer::NamespaceEntries;
-use crate::gen::out::OutFile;
-use crate::gen::{include, Opt};
+use crate::gen::out::{Content, OutFile};
+use crate::gen::Opt;
 use crate::syntax::atom::Atom::{self, *};
 use crate::syntax::symbol::Symbol;
 use crate::syntax::{
-    mangle, Api, CppName, Enum, ExternFn, ExternType, ResolvableName, Signature, Struct, Type,
-    Types, Var,
+    mangle, Api, CppName, Enum, ExternFn, ExternType, IncludeKind, ResolvableName, Signature,
+    Struct, Type, Types, Var,
 };
 use proc_macro2::Ident;
 use std::collections::HashMap;
@@ -40,7 +41,7 @@
         write_generic_instantiations(out);
     }
 
-    write!(out.front, "{}", out.include);
+    write_includes(&mut out.front, &out.include);
 
     out_file
 }
@@ -247,6 +248,58 @@
     }
 }
 
+fn write_includes(out: &mut Content, include: &Includes) {
+    for include in &include.custom {
+        match include.kind {
+            IncludeKind::Quoted => {
+                writeln!(out, "#include \"{}\"", include.path.escape_default());
+            }
+            IncludeKind::Bracketed => {
+                writeln!(out, "#include <{}>", include.path);
+            }
+        }
+    }
+
+    if include.array {
+        writeln!(out, "#include <array>");
+    }
+    if include.cstddef {
+        writeln!(out, "#include <cstddef>");
+    }
+    if include.cstdint {
+        writeln!(out, "#include <cstdint>");
+    }
+    if include.cstring {
+        writeln!(out, "#include <cstring>");
+    }
+    if include.exception {
+        writeln!(out, "#include <exception>");
+    }
+    if include.memory {
+        writeln!(out, "#include <memory>");
+    }
+    if include.new {
+        writeln!(out, "#include <new>");
+    }
+    if include.string {
+        writeln!(out, "#include <string>");
+    }
+    if include.type_traits {
+        writeln!(out, "#include <type_traits>");
+    }
+    if include.utility {
+        writeln!(out, "#include <utility>");
+    }
+    if include.vector {
+        writeln!(out, "#include <vector>");
+    }
+    if include.basetsd {
+        writeln!(out, "#if defined(_WIN32)");
+        writeln!(out, "#include <basetsd.h>");
+        writeln!(out, "#endif");
+    }
+}
+
 fn write_builtins(out: &mut OutFile) {
     out.begin_block("namespace rust");
     out.begin_block("inline namespace cxxbridge05");