diff --git a/dos/config.h b/dos/config.h
index 634c5cc8..415cd5a8 100644
--- a/dos/config.h
+++ b/dos/config.h
@@ -81,9 +81,6 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #define HAVE_INTTYPES_H 1
 
-/* Define to 1 if you have the <limits.h> header file. */
-#define HAVE_LIMITS_H 1
-
 /* Define to 1 if .lz (lzip) decompression support is enabled. */
 #define HAVE_LZIP_DECODER 1
 
@@ -108,15 +105,6 @@
 /* Define to 1 if you have the <stdint.h> header file. */
 #define HAVE_STDINT_H 1
 
-/* Define to 1 if you have the <stdlib.h> header file. */
-#define HAVE_STDLIB_H 1
-
-/* Define to 1 if you have the <string.h> header file. */
-#define HAVE_STRING_H 1
-
-/* Define to 1 if you have the <sys/time.h> header file. */
-#define HAVE_SYS_TIME_H 1
-
 /* Define to 1 if you have the 'utimes' function. */
 #define HAVE_UTIMES 1