diff --git a/simgear/math/SGVec2.hxx b/simgear/math/SGVec2.hxx
index 6b49bc61..0409ee44 100644
--- a/simgear/math/SGVec2.hxx
+++ b/simgear/math/SGVec2.hxx
@@ -18,6 +18,10 @@
 #ifndef SGVec2_H
 #define SGVec2_H
 
+#if defined ( __CYGWIN__ )
+#include <ieeefp.h>
+#endif
+
 #include <osg/Vec2f>
 #include <osg/Vec2d>
 
diff --git a/simgear/scene/material/matlib.cxx b/simgear/scene/material/matlib.cxx
index 9c02cb96..5bf353cb 100644
--- a/simgear/scene/material/matlib.cxx
+++ b/simgear/scene/material/matlib.cxx
@@ -33,6 +33,10 @@
 #  include <windows.h>
 #endif
 
+#if defined ( __CYGWIN__ )
+#include <ieeefp.h>
+#endif
+
 #include <simgear/compiler.h>
 #include <simgear/constants.h>
 #include <simgear/structure/exception.hxx>
diff --git a/simgear/scene/sky/sphere.cxx b/simgear/scene/sky/sphere.cxx
index bbd68694..43d20e1c 100644
--- a/simgear/scene/sky/sphere.cxx
+++ b/simgear/scene/sky/sphere.cxx
@@ -20,6 +20,9 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 // $Id$
+#ifdef __CYGWIN__
+#include <ieeefp.h>
+#endif
 
 
 #include <simgear/compiler.h>
diff --git a/simgear/scene/sky/stars.cxx b/simgear/scene/sky/stars.cxx
index bd31aedc..55616f68 100644
--- a/simgear/scene/sky/stars.cxx
+++ b/simgear/scene/sky/stars.cxx
@@ -27,6 +27,10 @@
 #  include <simgear_config.h>
 #endif
 
+#ifdef __CYGWIN__
+#include <ieeefp.h>
+#endif
+
 #include <simgear/compiler.h>
 #include <simgear/constants.h>
 #include <simgear/debug/logstream.hxx>
diff --git a/simgear/structure/SGAtomic.hxx b/simgear/structure/SGAtomic.hxx
index 29c23c25..4029f352 100644
--- a/simgear/structure/SGAtomic.hxx
+++ b/simgear/structure/SGAtomic.hxx
@@ -28,7 +28,7 @@
 #elif defined(__sgi) && defined(_COMPILER_VERSION) && (_COMPILER_VERSION>=730)
 // No need to include something. Is a Compiler API ...
 # define SGATOMIC_USE_MIPSPRO_BUILTINS
-#elif defined(WIN32) 
+#elif defined(WIN32)  && !defined ( __CYGWIN__ )
 # include <windows.h>
 # define SGATOMIC_USE_WIN32_INTERLOCKED
 #else