Update src/bootstrap/src/core/builder.rs

Co-authored-by: Onur Özkan <onurozkan.dev@outlook.com>

Author: scottmcm

src/bootstrap/src/core/builder.rs

@@ -2072,7 +2072,7 @@ impl<'a> Builder<'a> {
             // during incremental builds" heuristic for the standard library.
             rustflags.arg("-Zinline-mir");
 
-            // always pass this after the next `#[cfg(bootstrap)]` update.
+            // FIXME: always pass this after the next `#[cfg(bootstrap)]` update.
             if compiler.stage != 0 {
                 // Similarly, we need to keep debug info for functions inlined into other std functions,
                 // even if we're not going to output debuginfo for the crate we're currently building,