Fix bug in library output filename construction: /tmp/foo.rc was being linked as lib/tmp/foo-<hash>-<vers>.so not /tmp/foo-<hash>-<vers>.so

Author: graydon

src/comp/back/link.rs

@@ -588,9 +588,16 @@ fn link_binary(sess: session::session,
         let long_libname =
             std::os::dylib_filename(#fmt("%s-%s-%s",
                                          lm.name, lm.extras_hash, lm.vers));
+        log "link_meta.name: " + lm.name;
+        log "long_libname: " + long_libname;
+        log "out_filename: " + out_filename;
+        log "dirname(out_filename): " + fs::dirname(out_filename);
+
         fs::connect(fs::dirname(out_filename), long_libname)
     } else { out_filename };
 
+    log "output: " + output;
+
     // The default library location, we need this to find the runtime.
     // The location of crates will be determined as needed.
     let stage: str = "-L" + sess.filesearch().get_target_lib_path();

src/comp/driver/rustc.rs

@@ -561,7 +561,10 @@ fn build_output_filenames(ifile: str, ofile: option::t<str>,
         obj_filename = base_filename + "." + suffix;
 
         if sess.building_library() {
-            saved_out_filename = std::os::dylib_filename(base_filename);
+            let dirname = fs::dirname(base_filename);
+            let basename = fs::basename(base_filename);
+            let dylibname = std::os::dylib_filename(basename);
+            saved_out_filename = fs::connect(dirname, dylibname);
         } else {
             saved_out_filename = base_filename;
         }