diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -90,6 +90,7 @@ SRCS="`< $ROOT_DIR/source.list tr '\r' '
 		if ($0 == "PSP"         && "'$os'" != "PSP")               { next; }
 		if ($0 == "DEDICATED"   && "'$enable_dedicated'" != "1")   { next; }
 		if ($0 == "COCOA"       && "'$with_cocoa'" == "0")         { next; }
+		if ($0 == "DOS"         && "'$os'" != "DOS")               { next; }
 		if ($0 == "BEOS"        && "'$os'" != "BEOS")              { next; }
 		if ($0 == "WIN32"       && "'$os'" != "MINGW" &&
 		                "'$os'" != "CYGWIN" && "'$os'" != "MSVC" ) { next; }