enabling alpha on msw colour

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41526 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/colour.cpp

@@ -68,6 +68,7 @@ void wxColour::Init()
 {
     m_isInit = false;
     m_pixel = 0;
+    m_alpha =
     m_red =
     m_blue =
     m_green = 0;
@@ -78,11 +79,12 @@ wxColour::~wxColour()
 }
 
 void wxColour::InitRGBA(unsigned char r, unsigned char g, unsigned char b,
-                        unsigned char WXUNUSED(a))
+                        unsigned char a)
 {
     m_red = r;
     m_green = g;
     m_blue = b;
+    m_alpha = a;
     m_isInit = true;
     m_pixel = PALETTERGB(m_red, m_green, m_blue);
 }