[PATCH] comctl32/toolbar: Correctly draw disabled toolbar button which contains 32 bpp bitmap with alpha channel.

[Ziqing Hui]

According to my tests, on v6 comctl32, here is the disabled toolbar button appearance in different situation:

* 32bpp with alpha channel: Grayscale (This is not supported before v6)
* 32bpp without alpha channel ("without alpha channel" means each pixel's alpha value is set to 0): Solid color
* not 32bpp (maybe 24bpp, 16bpp etc.): Solid color

This patch handle the first situation for wine.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=24784
Signed-off-by: Ziqing Hui 
---
 dlls/comctl32/toolbar.c | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)