allow overload operator SQR()

Author: jayrm

changelog.txt

@@ -11,6 +11,7 @@ Version 1.06.0
 - Windows API binding updated to additionally support _WIN32_WINNT &h0501, &h0600, &h0601
 - Under X11, ScreenControl GET_WINDOW_HANDLE places the Display ptr in param2
 - Updated bindings: SDL2 2.0.6, SDL2_image 2.0.1, SDL2_mixer 2.0.1, SDL2_net 2.0.1, SDL2_ttf 2.0.14
+- allow overload operator SQR()
 
 [fixed]
 - win/d3dx9.bi no longer has a hard-coded #inclib "d3dx9d". d3dx9d.dll is apparently not a generally valid choice. In practice programs have to be linked against d3dx9_33.dll or d3dx9_39.dll, etc.