1 files changed, 16 insertions, 16 deletions

diff --git a/nix/libstore/builtins.hh b/nix/libstore/builtins.hh
index 602a5a1c58d..d5d09e27bc0 100644
--- a/nix/libstore/builtins.hh
+++ b/nix/libstore/builtins.hh
@@ -25,20 +25,20 @@
 
 namespace nix {
 
-    inline bool isBuiltin(const Derivation & drv)
-    {
-        return string(drv.builder, 0, 8) == "builtin:";
-    }
-
-    /* Build DRV, which lives at DRVPATH.  */
-    typedef void (*derivationBuilder) (const Derivation &drv,
-                                       const std::string &drvPath,
-                                       const std::string &output);
-
-    /* Return the built-in builder called BUILDER, or NULL if none was
-       found.  */
-    derivationBuilder lookupBuiltinBuilder(const std::string &builder);
-
-    /* Return the list of supported built-in builder names.  */
-    std::list<std::string> builtinBuilderNames();
+inline bool isBuiltin(const Derivation & drv)
+{
+        return drv.builder.starts_with("builtin:");
+}
+
+/* Build DRV, which lives at DRVPATH.  */
+typedef void (*derivationBuilder) (const Derivation &drv,
+                   const std::string &drvPath,
+                                   const std::string &output);
+
+/* Return the built-in builder called BUILDER, or NULL if none was
+   found.  */
+derivationBuilder lookupBuiltinBuilder(const std::string &builder);
+
+/* Return the list of supported built-in builder names.  */
+std::list<std::string> builtinBuilderNames();
 }