diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -937,7 +937,7 @@
           >,
           FunctionSpec<
               "difftime",
-              RetValSpec<DoubleType>>,
+              RetValSpec<DoubleType>,
               [
                   ArgSpec<TimeTType>,
                   ArgSpec<TimeTType>,