diff --git a/lib-src/libnyquist/nyquist/xlisp/security.c b/lib-src/libnyquist/nyquist/xlisp/security.c
index 954948b78..d819e34e6 100644
--- a/lib-src/libnyquist/nyquist/xlisp/security.c
+++ b/lib-src/libnyquist/nyquist/xlisp/security.c
@@ -5,7 +5,7 @@
 
 #include <stdlib.h>
 #include "switches.h"
-#if defined(UNIX) || defined(__APPLE__)
+#if defined(UNIX) || defined(__APPLE__) || defined(__CYGWIN__)
 #include <unistd.h>
 #endif
 #ifdef WIN32
diff --git a/lib-src/libnyquist/nyquist/xlisp/xlisp.h b/lib-src/libnyquist/nyquist/xlisp/xlisp.h
index 736ce37bb..44d52c358 100644
--- a/lib-src/libnyquist/nyquist/xlisp/xlisp.h
+++ b/lib-src/libnyquist/nyquist/xlisp/xlisp.h
@@ -161,7 +161,7 @@ extern long ptrtoabs();
 #endif
 
 /* Linux on Pentium */
-#if defined(__linux__) || defined(__GLIBC__)
+#if defined(__linux__) || defined(__GLIBC__) || defined(__CYGWIN__)
 #define AFMT            "%p"
 #include <inttypes.h>
 #include <endian.h>