Fixes for Cywin gcc3.x build in GL and Math headers.

Fix for VS build in osgshadowtexture.

include/osg/GL

@@ -68,8 +68,9 @@
         #define DECLSPEC_IMPORT    __declspec(dllimport)
         #define WINGDIAPI DECLSPEC_IMPORT
     #endif
-           // XXX This is from Win32's <ctype.h> 
-    #ifndef _WCHAR_T_DEFINED
+           // XXX This is from Win32's <ctype.h>
+
+    #if !defined(_WCHAR_T_DEFINED) && !(defined(__GNUC__)&&(__GNUC__ == 3))
         typedef unsigned short wchar_t;
         #define _WCHAR_T_DEFINED
     #endif

include/osg/Math

@@ -7,6 +7,10 @@
 
 #include <math.h>
 
+#if defined(__GNUC__) && defined(WIN32)
+#  include <iostream>
+#endif
+
 // for OSX users :
 // comment in if you want backwards compatibility with 10.1.x versions
 // otherwise you'll have problems with missing floorf and __isnan*()