Don't provide backend_optimization_level query for extern crates

Author: bjorn3

compiler/rustc_codegen_ssa/src/base.rs

@@ -783,7 +783,7 @@ impl CrateInfo {
     }
 }
 
-pub fn provide_both(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers) {
     providers.backend_optimization_level = |tcx, cratenum| {
         let for_speed = match tcx.sess.opts.optimize {
             // If globally no optimisation is done, #[optimize] has no effect.

compiler/rustc_codegen_ssa/src/lib.rs

@@ -160,13 +160,12 @@ pub struct CodegenResults {
 
 pub fn provide(providers: &mut Providers) {
     crate::back::symbol_export::provide(providers);
-    crate::base::provide_both(providers);
+    crate::base::provide(providers);
     crate::target_features::provide(providers);
 }
 
 pub fn provide_extern(providers: &mut Providers) {
     crate::back::symbol_export::provide_extern(providers);
-    crate::base::provide_both(providers);
 }
 
 /// Checks if the given filename ends with the `.rcgu.o` extension that `rustc`