[Bug 27929] New: Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

Summary: Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion
                    with Xcode 4.1
           Product: Wine
           Version: 1.3.25
          Platform: x86-64
        OS/Version: other
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: -unknown
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

I have compiled Wine 1.3.25 on Mac OS X 10.7, with the latest developer tools
installed (Xcode 4.1).
Trying to launch any wine program, even winemine, results in it crashing with
the message "Bus error: 10".
Running wine inside gdb, and with WINEDEBUG=+relay, shows that the crash occurs
while doing:

0045:Call user32.LoadIconA(403b0000,403b5a84 "WINEMINE") ret=403b1899

Specifically, it crashes inside create_alpha_bitmap, soon after the call to
StretchDIBits returns, inside the loop that does alpha premultiplication. By
disassembling I found that the crash occurs in the line

ptr[0] = ptr[0] * alpha / 255;

when attempting to write back the value into ptr[0]. It occurs on the very
first iterations of the loop.

I tried googling a bit, and this seems to be the same problem that was
discussed here:
http://www.winehq.org/pipermail/wine-devel/2011-January/088553.html

But that conversation was back in January, and it's unclear if any resolution
was reached.
Anyway, since this problem seems to make Wine completely unusable on Lion, and
can be reproduced entirely within wine, I think it should be considered both
easy to reproduce (as long as you have access to a Mac) and very urgent to fix