0028838: Configuration - undefine macros coming from X11 headers in place of collision

The macros Status, Convex, Opposite, FillSolid (coming from X11 headers)
are now undefined in place of definition of methods with same name in OCCT headers.
The usage of variables with name Status is now avoided.

GL_GLEXT_LEGACY is now defined only if not already defined.

The macros AddPrinter (coming from WinAPI headers) is now undefined
within Message_Messenger class definition having method with the same name.
CurrentDirectory macro is now undefined in OSD_Process.hxx.

src/math/math_IntegerVector.hxx

@@ -17,10 +17,10 @@
 
 #include <math_SingleTab.hxx>
 
-class Standard_DimensionError;
-class Standard_DivideByZero;
-class Standard_RangeError;
-class math_Matrix;
+// resolve name collisions with X11 headers
+#ifdef Opposite
+  #undef Opposite
+#endif
 
 //! This class implements the real IntegerVector abstract data type.
 //! IntegerVectors can have an arbitrary range which must be define at

src/math/math_Matrix.hxx

@@ -27,13 +27,11 @@
 #include <Standard_Address.hxx>
 #include <math_Vector.hxx>
 #include <Standard_OStream.hxx>
-class Standard_DimensionError;
-class Standard_RangeError;
-class Standard_DivideByZero;
-class math_NotSquare;
-class math_SingularMatrix;
-class math_Vector;
 
+// resolve name collisions with X11 headers
+#ifdef Opposite
+  #undef Opposite
+#endif
 
 //! This class implements the real matrix abstract data type.
 //! Matrixes can have an arbitrary range which must be defined

src/math/math_Vector.hxx

@@ -19,10 +19,11 @@
 #include <gp_XY.hxx>
 #include <gp_XYZ.hxx>
 
-class Standard_DimensionError;
-class Standard_DivideByZero;
-class Standard_RangeError;
-class Standard_NullValue;
+// resolve name collisions with X11 headers
+#ifdef Opposite
+  #undef Opposite
+#endif
+
 class math_Matrix;
 
 //! This class implements the real vector abstract data type.