refactor(treewide): get rid of compile time build environment introspection

It's cursed and not very useful. Still a few uses of ctor left, but oh well.

src/core/debug.rs

@@ -62,7 +62,7 @@ pub const INFO_SPAN_LEVEL: Level = if cfg!(debug_assertions) {
 pub static DEBUGGER: LazyLock<bool> =
 	LazyLock::new(|| env::var("_").unwrap_or_default().ends_with("gdb"));
 
-#[cfg_attr(debug_assertions, crate::ctor)]
+#[cfg_attr(debug_assertions, ctor::ctor)]
 #[cfg_attr(not(debug_assertions), allow(dead_code))]
 fn set_panic_trap() {
 	if !*DEBUGGER {