[Bug 18601] New: Google Sketchup 7 crashes early in wine's imm.dll

http://bugs.winehq.org/show_bug.cgi?id=18601

Summary: Google Sketchup 7 crashes early in wine's imm.dll
           Product: Wine
           Version: 1.1.21
          Platform: Other
               URL: http://sketchup.google.com
        OS/Version: other
            Status: NEW
          Keywords: download, patch, regression
          Severity: normal
          Priority: P2
         Component: -unknown
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Not sure when this started; I first noticed it about a month ago.

Sketchup 7 installs, but when you start it up, it crashes with

trace:imm:DllMain 0x7ca20000, 2, (nil)
trace:imm:DllMain 0x7ca20000, 3, (nil)
wine: Unhandled page fault on read access to 0x00000006 at address 0x7ca28f69
(thread 0009), starting debugger...
Backtrace:
=>0 0x7ca28f69 ImmAssociateContext+0x229(hWnd=0x100b6, hIMC=(nil))
[imm32/imm.c:476] in imm32 (0x0032f2d4)
  1 0x02ca9a9e in xul (+0xaa9a9e) (0x0032f304)

or
wine: Unhandled page fault on write access to 0x00000006 at address 0x7cc626d1
(thread 0009), starting debugger...
Backtrace:
=>0 0x7cc626d1 ImmGetContext+0x61(hWnd=0x10038) [imm32/imm.c:1381] in imm32
(0x0032f938)
  1 0x7cc627dd ImmProcessKey+0x3d(hwnd=0x10038, hKL=0x4090409, vKey=39,
lKeyData=21823489, unknown=0) [imm32/imm.c:2775] in imm32 (0x0032fa88)
  2 0x7eb28dec peek_message+0x238c(msg=0x142a40, hwnd=(nil), first=0,
last=4294967295, flags=83820545, changed_mask=1279)
[dlls/user32/message.c:1768] in user32 (0x0032fdb8)
1381            data->IMC.hWnd = hWnd;

In both cases it looks like a bogus small value is in
IMM_GetThreadData()->defaultContext
Ignoring that and replacing it with NULL seems to work around
the problem; see attached patch.