diff --git a/Headers/CoreGraphics/CGAffineTransform.h b/Headers/CoreGraphics/CGAffineTransform.h
index d052f78..1b14fbe 100644
--- a/Headers/CoreGraphics/CGAffineTransform.h
+++ b/Headers/CoreGraphics/CGAffineTransform.h
@@ -34,6 +34,8 @@ extern "C" {
 
 /* Data Types */
 
+// Defined by CoreFoundation/CFCGTypes.h in GNUstep Base
+#ifndef CF_DEFINES_CG_TYPES
 typedef struct CGAffineTransform
 {
   CGFloat a;
@@ -43,6 +45,7 @@ typedef struct CGAffineTransform
   CGFloat tx;
   CGFloat ty;
 } CGAffineTransform;
+#endif // !CF_DEFINES_CG_TYPES
 
 /* Constants */
 
diff --git a/Headers/CoreGraphics/CGGeometry.h b/Headers/CoreGraphics/CGGeometry.h
index 9d2a1d9..d35e4b7 100644
--- a/Headers/CoreGraphics/CGGeometry.h
+++ b/Headers/CoreGraphics/CGGeometry.h
@@ -33,6 +33,8 @@
 extern "C" {
 #endif
 
+// Defined by CoreFoundation/CFCGTypes.h in GNUstep Base
+#ifndef CF_DEFINES_CG_TYPES
 typedef NSPoint CGPoint;
 typedef NSSize CGSize;
 typedef NSRect CGRect;
@@ -46,6 +48,8 @@ enum
   CGRectMaxXEdge = 2,
   CGRectMaxYEdge = 3
 };
+#endif // !CF_DEFINES_CG_TYPES
+
 typedef int CGRectEdge;
 
 /** Point at 0,0 */
@@ -90,12 +94,15 @@ OP_GEOM_SCOPE CGSize CGSizeMake(CGFloat width, CGFloat height) OP_GEOM_ATTR;
 /** Returns a CGRect having point of origin (x, y) and size (width, height). */
 OP_GEOM_SCOPE CGRect CGRectMake(CGFloat x, CGFloat y, CGFloat width, CGFloat height) OP_GEOM_ATTR;
 
+// Defined by Foundation/NSGeometry.h in GNUstep Base
+#ifndef CF_DEFINES_CG_TYPES
 OP_GEOM_SCOPE CGRect NSRectToCGRect(NSRect rect);
 OP_GEOM_SCOPE NSRect NSRectFromCGRect(CGRect rect);
 OP_GEOM_SCOPE CGPoint NSPointToCGPoint(NSPoint point);
 OP_GEOM_SCOPE NSPoint NSPointFromCGPoint(CGPoint point);
 OP_GEOM_SCOPE NSSize NSSizeFromCGSize(CGSize size);
 OP_GEOM_SCOPE CGSize NSSizeToCGSize(NSSize size);
+#endif // !CF_DEFINES_CG_TYPES
 
 /** Returns an equivalent rect which has positive width and heght. */
 OP_GEOM_SCOPE CGRect CGRectStandardize(CGRect rect) OP_GEOM_ATTR;
@@ -329,6 +336,8 @@ OP_GEOM_SCOPE CGRect CGRectMake(CGFloat x, CGFloat y, CGFloat width, CGFloat hei
   return rect;
 }
 
+// Defined by Foundation/NSGeometry.h in GNUstep Base
+#ifndef CF_DEFINES_CG_TYPES
 OP_GEOM_SCOPE CGRect NSRectToCGRect(NSRect rect)
 {
   CGRect cgrect;
@@ -386,6 +395,7 @@ OP_GEOM_SCOPE CGSize NSSizeToCGSize(NSSize size)
   cgsize.height = size.height;
   return cgsize;
 }
+#endif // !CF_DEFINES_CG_TYPES
 
 OP_GEOM_SCOPE CGRect CGRectStandardize(CGRect rect)
 {