diff --git a/README.markdown b/README.markdown
index 912ef08..3902c83 100644
--- a/README.markdown
+++ b/README.markdown
@@ -152,3 +152,12 @@ Open source implementations of protcol
 * Teensy (C) https://github.com/jkerdels/open_imme/tree/master/tools/teensy-prog
 * Linux GPIO sysfs (C) https://github.com/ffainelli/cc2530prog
 
+Building for Windows
+--------------------
+
+`cctl-prog` is currently built for Windows using the mingw32 cross compiler from Linux.
+
+    make -f Makefile.mingw32
+
+Compiling cctl-prog with cygwin's GCC may not work.
+
diff --git a/cctl-prog/cctl-prog.c b/cctl-prog/cctl-prog.c
index f717c2a..98620bb 100644
--- a/cctl-prog/cctl-prog.c
+++ b/cctl-prog/cctl-prog.c
@@ -9,6 +9,10 @@
 #include <getopt.h>
 #include <sys/time.h>
 
+#ifdef __CYGWIN__
+#define WIN32 1
+#endif
+
 #define SERIAL_TIMEOUT 2
 
 #ifndef WIN32
@@ -18,8 +22,6 @@
 #include <windows.h>
 #include <wincon.h>
 #include <time.h>
-#define O_NOCTTY 0
-#define O_NDELAY 0
 #define B115200 115200
 #endif
 
diff --git a/cctl-prog/hex.c b/cctl-prog/hex.c
index d1eaaa4..00ebcce 100644
--- a/cctl-prog/hex.c
+++ b/cctl-prog/hex.c
@@ -7,6 +7,10 @@
 #include <string.h>
 #include <stdlib.h>
 
+#ifdef __CYGWIN__
+#define WIN32 1
+#endif
+
 #ifndef WIN32
 #include <arpa/inet.h>
 #else