diff --git a/dmd/mars.c b/dmd/mars.c
index 285412be..3313309b 100644
--- a/dmd/mars.c
+++ b/dmd/mars.c
@@ -66,9 +66,7 @@ Global::Global()
     bc_ext  = "bc";
     s_ext   = "s";
     obj_ext = "o";
-#if _WIN32
     obj_ext_alt = "obj";
-#endif
 
     copyright = "Copyright (c) 1999-2012 by Digital Mars and Tomas Lindquist Olsen";
     written = "written by Walter Bright and Tomas Lindquist Olsen";
diff --git a/dmd/mars.h b/dmd/mars.h
index 4afc4eb0..8ca5f002 100644
--- a/dmd/mars.h
+++ b/dmd/mars.h
@@ -321,12 +321,10 @@ struct Global
     const char *mars_ext;
     const char *sym_ext;
     const char *obj_ext;
-#if _WIN32
-    char *obj_ext_alt;
-#endif
-    char *ll_ext;
-    char *bc_ext;
-    char *s_ext;
+    const char *obj_ext_alt;
+    const char *ll_ext;
+    const char *bc_ext;
+    const char *s_ext;
     const char *lib_ext;
     const char *dll_ext;
     const char *doc_ext;        // for Ddoc generated files
diff --git a/dmd/module.c b/dmd/module.c
index f8b12287..248cdc75 100644
--- a/dmd/module.c
+++ b/dmd/module.c
@@ -247,7 +247,7 @@ void Module::buildTargetFiles(bool singleObj)
         else if (global.params.output_s)
             objfile = Module::buildFilePath(global.params.objname, global.params.objdir, global.s_ext);
         else
-            objfile = Module::buildFilePath(global.params.objname, global.params.objdir, global.obj_ext);
+            objfile = Module::buildFilePath(global.params.objname, global.params.objdir, global.params.os == OSWindows ? global.obj_ext_alt : global.obj_ext);
     }
     if(doDocComment && !docfile)
         docfile = Module::buildFilePath(global.params.docname, global.params.docdir, global.doc_ext);