back/winlib: fix the dash pattern type in the win32 graphics state (#143)

The dash pattern was declared as an array of CGFloat pointers rather than an
array of CGFloat, so -getLineDash:count:phase: filled it with dash lengths cast
to pointers and the pen pattern was built from the pointer values.  It also did
not compile on a modern compiler.  Declare it as an array of CGFloat.

Author: DTW-Thalion

Source/winlib/WIN32GState.m

@@ -1375,7 +1375,7 @@ - (void) setStyle: (HDC)hDC
   if (patternCount > 0)
     {
       NSInteger i = 0;
-      CGFloat* thePattern[patternCount];
+      CGFloat thePattern[patternCount];
       CGFloat phase = 0.0;
 
       penStyle = PS_GEOMETRIC | PS_USERSTYLE;