rustc: Stop exporting various things from driver::diagnostic

src/comp/driver/diagnostic.rs

@@ -3,8 +3,7 @@
 import syntax::codemap;
 import codemap::span;
 
-export diagnostictype, warning, error, note;
-export print_diagnostic, emit_warning, emit_error, emit_note;
+export emit_warning, emit_error, emit_note;
 
 tag diagnostictype {
     warning;

src/comp/driver/driver.rs

@@ -580,7 +580,7 @@ fn build_output_filenames(ifile: str,
 }
 
 fn early_error(msg: str) -> ! {
-    diagnostic::print_diagnostic("", diagnostic::error, msg);
+    diagnostic::emit_error(none, msg);
     fail;
 }