rustc_session: make cli early_fatal messages translatable

Author: GrigorenkoPV

compiler/rustc_session/messages.ftl

@@ -14,6 +14,8 @@ session_crate_name_empty = crate name must not be empty
 
 session_crate_name_invalid = crate names cannot start with a `-`, but `{$s}` has a leading hyphen
 
+session_empty_search_path = empty search path given via `-L`
+
 session_expr_parentheses_needed = parentheses are required to parse this as an expression
 
 session_failed_to_create_profiler = failed to create profiler: {$err}
@@ -86,6 +88,9 @@ session_profile_sample_use_file_does_not_exist = file `{$path}` passed to `-C pr
 
 session_profile_use_file_does_not_exist = file `{$path}` passed to `-C profile-use` does not exist
 
+session_rustc_builtin =
+    the `-Z unstable-options` flag must also be passed to enable the use of `@RUSTC_BUILTIN`
+
 session_sanitizer_cfi_canonical_jump_tables_requires_cfi = `-Zsanitizer-cfi-canonical-jump-tables` requires `-Zsanitizer=cfi`
 
 session_sanitizer_cfi_generalize_pointers_requires_cfi = `-Zsanitizer-cfi-generalize-pointers` requires `-Zsanitizer=cfi` or `-Zsanitizer=kcfi`

compiler/rustc_session/src/search_paths.rs

@@ -4,7 +4,7 @@ use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use rustc_target::spec::TargetTriple;
 
 use crate::filesearch::make_target_lib_path;
-use crate::EarlyDiagCtxt;
+use crate::{fluent_generated, EarlyDiagCtxt};
 
 #[derive(Clone, Debug)]
 pub struct SearchPath {
@@ -73,20 +73,15 @@ impl SearchPath {
         let dir = match path.strip_prefix("@RUSTC_BUILTIN") {
             Some(stripped) => {
                 if !is_unstable_enabled {
-                    #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-                    early_dcx.early_fatal(
-                        "the `-Z unstable-options` flag must also be passed to \
-                         enable the use of `@RUSTC_BUILTIN`",
-                    );
+                    early_dcx.early_fatal(fluent_generated::session_rustc_builtin);
                 }
 
                 make_target_lib_path(sysroot, triple.triple()).join("builtin").join(stripped)
             }
             None => PathBuf::from(path),
         };
         if dir.as_os_str().is_empty() {
-            #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-            early_dcx.early_fatal("empty search path given via `-L`");
+            early_dcx.early_fatal(fluent_generated::session_empty_search_path);
         }
 
         Self::new(kind, dir)