Recognize MSYS/MINGW environment.

config

diff --git a/config b/config
index 71ada7b..02d7de0 100755
--- a/config
+++ b/config
@@ -337,6 +337,9 @@
 	echo "mips-sony-newsos4"; exit 0;
 	;;
 
+    MINGW*)
+	echo "${MACHINE}-whatever-mingw"; exit 0;
+	;;
     CYGWIN*)
 	case "$RELEASE" in
 	    [bB]*|1.0|1.[12].*)