Refactor rect.c to C++

src/openrct2/drawing/Rect.cpp

@@ -19,6 +19,9 @@
 #include "../platform/platform.h"
 #include "drawing.h"
 
+extern "C"
+{
+
 /**
  * Draw a rectangle, with optional border or fill
  *
@@ -114,3 +117,5 @@ void gfx_fill_rect_inset(rct_drawpixelinfo* dpi, sint16 left, sint16 top, sint16
         }
     }
 }
+
+}