in aws-lc-sys/builder/main.rs [603:610]
fn use_prebuilt_nasm() -> bool {
target_os() == "windows"
&& target_arch() == "x86_64"
&& !is_no_asm()
&& !test_nasm_command()
&& (Some(true) == allow_prebuilt_nasm()
|| (allow_prebuilt_nasm().is_none() && cfg!(feature = "prebuilt-nasm")))
}