#[cfg(any(test, feature = "std"))]
extern crate core;
-#[cfg(any(test, feature = "_test_utils"))] extern crate hex;
+extern crate hex;
#[cfg(any(test, feature = "_test_utils"))] extern crate regex;
#[cfg(not(feature = "std"))] extern crate core2;
+#[cfg(not(feature = "std"))] extern crate libm;
#[cfg(ldk_bench)] extern crate criterion;