diff --git a/src/fileio.cpp b/src/fileio.cpp
index 3b18da7a67..253ad8ebb3 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -22,7 +22,7 @@
 #include <Path.h>
 #include <storage/FindDirectory.h>
 #else
-#ifdef OPENBSD
+#if defined(OPENBSD) || defined(DOS)
 #include <unistd.h>
 #endif
 #include <pwd.h>
diff --git a/src/stdafx.h b/src/stdafx.h
index 4ea5ddc586..649b80d8dc 100644
--- a/src/stdafx.h
+++ b/src/stdafx.h
@@ -225,6 +225,15 @@
 
 #endif /* defined(_MSC_VER) */
 
+#if defined(DOS)
+	/* The DOS port does not have all signals/signal functions. */
+	#define strsignal(sig) ""
+	/* Use 'no floating point' for bus errors; SIGBUS does not
+	 * exist for does, SIGNOFP not for other platforms. So it's
+	 * fairly safe the interchange those. */
+	#define SIGBUS SIGNOFP
+#endif
+
 #if defined(WINCE)
 	#define strdup _strdup
 #endif /* WINCE */