gnu: rust-cfg-if-0.1: Don't skip build.

* gnu/packages/crates-io.scm (rust-cfg-if-0.1)[arguments]: Don't skip
build.

gnu/packages/crates-io.scm

@@ -2841,8 +2841,7 @@ archive to be linked into Rustcode.")
           "08h80ihs74jcyp24cd75wwabygbbdgl05k6p5dmq8akbr78vv1a7"))))
     (build-system cargo-build-system)
     (arguments
-     `(#:skip-build? #t
-       #:cargo-inputs
+     `(#:cargo-inputs
        (("rust-compiler-builtins" ,rust-compiler-builtins-0.1)
         ("rust-rustc-std-workspace-core" ,rust-rustc-std-workspace-core-1.0))))
     (home-page "https://github.com/alexcrichton/cfg-if")