include: Avoid overflow (warning) in RGBA_MAKE.

[Gerald Pfeifer]

If the fourth parameter (named a) in RGBA_MAKE is an int, 
shifting it by 24 will result in a "potential overflow"
warning by GCC 6 and later.

Properly casting to unsigned avoids this.

Gerald

Signed-off-by: Gerald Pfeifer <gerald at pfeifer.com>
---
 include/d3dtypes.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/d3dtypes.h b/include/d3dtypes.h
index 75aee55..908b2ce 100644
--- a/include/d3dtypes.h
+++ b/include/d3dtypes.h
@@ -53,7 +53,7 @@ typedef LONG D3DFIXED;
 #define RGBA_GETRED(rgb)        (((rgb) >> 16) & 0xff)
 #define RGBA_GETGREEN(rgb)      (((rgb) >> 8) & 0xff)
 #define RGBA_GETBLUE(rgb)       ((rgb) & 0xff)
-#define RGBA_MAKE(r, g, b, a)   ((D3DCOLOR) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b)))
+#define RGBA_MAKE(r, g, b, a)   ((D3DCOLOR) (((unsigned)(a) << 24) | ((r) << 16) | ((g) << 8) | (b)))
 
 #define D3DRGB(r, g, b) \
     (0xff000000 | ( ((LONG)((r) * 255)) << 16) | (((LONG)((g) * 255)) << 8) | (LONG)((b) * 255))
-- 
2.9.2