--- gcc/config/i386/xm-dos.h	2018/04/24 18:10:27	1.1
+++ gcc/config/i386/xm-dos.h	2018/04/24 18:23:23	1.1.1.2
@@ -6,6 +6,9 @@
 /* Use semicolons to separate elements of a path.  */
 #define PATH_SEPARATOR ';'
 
+/* Use backslashs to separate levels of directory.  */
+#define DIR_SEPARATOR '\\'
+
 /* Suffix for executable file names.  */
 #define EXECUTABLE_SUFFIX ".exe"