build.rs: silence needless borrows clippy warning

Clippy shouldn't probably even look at this file, since it is meant
for older compilers. Clippy "fixes" could lead to failure to work on
older toolchains.

Author: unleashed

build.rs

@@ -119,6 +119,7 @@ mod autocfg {
     #![allow(unknown_lints)]
     #![allow(bare_trait_objects)]
     #![allow(ellipsis_inclusive_range_patterns)]
+    #![allow(clippy::needless_borrows_for_generic_args)]
 
     use std::collections::HashSet;
     use std::env;