diff --git a/configure.ac b/configure.ac
index d202423b4..7360988eb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -242,11 +242,11 @@ base_LIBS="$LIBS"
 dnl check for glut location
 AC_CHECK_HEADER(GL/glut.h)
 if test "x$ac_cv_header_GL_glut_h" = "xyes"; then
-    AC_DEFINE([GLUT_H], <GL/glut.h>, [Define as glut.h include location])
+    AC_DEFINE([FG_GLUT_H], <GL/glut.h>, [Define as glut.h include location])
 else
     AC_CHECK_HEADER(GLUT/glut.h)
     if test "x$ac_cv_header_GLUT_glut_h" = "xyes"; then
-        AC_DEFINE([GLUT_H], <GLUT/glut.h>, [Define as glut.h include location])
+        AC_DEFINE([FG_GLUT_H], <GLUT/glut.h>, [Define as glut.h include location])
     else
         echo "Neither GL/glut.h nor GLUT/glut.h found.  Cannot continue"
         exit
diff --git a/src/GUI/gui.h b/src/GUI/gui.h
index 69d0026c6..18794e5a7 100644
--- a/src/GUI/gui.h
+++ b/src/GUI/gui.h
@@ -33,7 +33,7 @@
 #  include <windows.h>
 #endif
 
-#include GLUT_H                 // needed before pu.h
+#include FG_GLUT_H              // needed before pu.h
 
 #include <plib/pu.h>		// plib include
 
diff --git a/src/GUI/gui_local.cxx b/src/GUI/gui_local.cxx
index 018760e98..01aab18b2 100644
--- a/src/GUI/gui_local.cxx
+++ b/src/GUI/gui_local.cxx
@@ -6,7 +6,7 @@
 #  include <windows.h>
 #endif
 
-#include GLUT_H                 // needed before pu.h
+#include FG_GLUT_H          // needed before pu.h
 #include <plib/pu.h>        // plib include
 
 #include <FDM/flight.hxx>
diff --git a/src/GUI/mouse.cxx b/src/GUI/mouse.cxx
index 4f63d7c4f..10290f7d3 100644
--- a/src/GUI/mouse.cxx
+++ b/src/GUI/mouse.cxx
@@ -38,7 +38,7 @@
 #  include <windows.h>
 #endif
 
-#include GLUT_H
+#include FG_GLUT_H
 
 #if defined(FX) && defined(XMESA)
 #  include <GL/xmesa.h>
diff --git a/src/Include/config.h-msvc6 b/src/Include/config.h-msvc6
index 91c9e9b2d..fcb2b9152 100644
--- a/src/Include/config.h-msvc6
+++ b/src/Include/config.h-msvc6
@@ -189,8 +189,8 @@
 #define  ENABLE_AUDIO_SUPPORT
 #endif
 
-#ifndef  GLUT_H
-#define  GLUT_H   <GL/glut.h>
-#endif   // #ifndef GLUT_H
+#ifndef  FG_GLUT_H
+#define  FG_GLUT_H   <GL/glut.h>
+#endif   // #ifndef FG_GLUT_H
 
 // eof - config.h-msvc6 - single flightgear config.h file
diff --git a/src/Input/input.cxx b/src/Input/input.cxx
index cc6ca78fe..df0129559 100644
--- a/src/Input/input.cxx
+++ b/src/Input/input.cxx
@@ -37,7 +37,7 @@
 #include STL_STRING
 #include <vector>
 
-#include GLUT_H
+#include FG_GLUT_H
 
 #include <plib/pu.h>
 
diff --git a/src/Main/bootstrap.cxx b/src/Main/bootstrap.cxx
index 4f12ad1ee..6ee3eb150 100644
--- a/src/Main/bootstrap.cxx
+++ b/src/Main/bootstrap.cxx
@@ -48,7 +48,7 @@ SG_USING_STD(endl);
 #  include <float.h>
 #endif
 
-#include GLUT_H
+#include FG_GLUT_H
 
 #ifdef macintosh
 #  include <console.h>		// -dw- for command line dialog
diff --git a/src/Main/splash.cxx b/src/Main/splash.cxx
index 12e7bb6eb..56e0daff6 100644
--- a/src/Main/splash.cxx
+++ b/src/Main/splash.cxx
@@ -34,7 +34,7 @@
 #  include <windows.h>
 #endif
 
-#include GLUT_H
+#include FG_GLUT_H
 
 #include <string.h>
 
diff --git a/src/NetworkOLK/net_hud.cxx b/src/NetworkOLK/net_hud.cxx
index 941043676..18d480831 100644
--- a/src/NetworkOLK/net_hud.cxx
+++ b/src/NetworkOLK/net_hud.cxx
@@ -36,7 +36,7 @@
 #endif
 #include <math.h>
 
-#include GLUT_H
+#include FG_GLUT_H
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/src/NetworkOLK/network.cxx b/src/NetworkOLK/network.cxx
index f1ce49658..430c23752 100644
--- a/src/NetworkOLK/network.cxx
+++ b/src/NetworkOLK/network.cxx
@@ -35,7 +35,7 @@
 #endif
 #include <math.h>
 
-#include GLUT_H
+#include FG_GLUT_H
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/src/Time/light.hxx b/src/Time/light.hxx
index 40ae8ef79..4ae68a10a 100644
--- a/src/Time/light.hxx
+++ b/src/Time/light.hxx
@@ -38,7 +38,7 @@
 #  include <windows.h>
 #endif
 
-#include GLUT_H
+#include FG_GLUT_H
 
 #include <plib/sg.h>			// plib include