Defer writing builtins until after main content
diff --git a/gen/src/write.rs b/gen/src/write.rs
index 1b30446..9696a49 100644
--- a/gen/src/write.rs
+++ b/gen/src/write.rs
@@ -18,6 +18,7 @@
         writeln!(out.include, "#pragma once");
     }
 
+    pick_includes_and_builtins(out, apis);
     out.include.extend(&opt.include);
     for api in apis {
         if let Api::Include(include) = api {
@@ -25,11 +26,6 @@
         }
     }
 
-    pick_includes_and_builtins(out, apis);
-    write_builtins(out);
-
-    out.next_section();
-
     let apis_by_namespace = NamespaceEntries::new(apis);
 
     gen_namespace_forward_declarations(out, &apis_by_namespace);
@@ -40,6 +36,7 @@
         write_generic_instantiations(out);
     }
 
+    write_builtins(out);
     write_includes(out);
 
     out_file