[WINMM] Fix segfault.

[Sean Young]

Warcraft II was segfaulting in winmm (waveOutUnprepareHeader). While I was 
at it, I've also experimented with the uSize parameter on WinXP; verified 
for waveOutUnprepareHeader and waveOutPrepareHeader (sorry, don't have any 
others than WinXP available here).


Sean

Index: dlls/winmm/winmm.c
===================================================================
RCS file: /home/wine/wine/dlls/winmm/winmm.c,v
retrieving revision 1.31
diff -u -r1.31 winmm.c
--- dlls/winmm/winmm.c	24 Feb 2004 01:02:01 -0000	1.31
+++ dlls/winmm/winmm.c	25 Feb 2004 20:51:53 -0000
@@ -2607,7 +2607,8 @@
 
     TRACE("(%p, %p, %u);\n", hWaveOut, lpWaveOutHdr, uSize);
 
-    if (lpWaveOutHdr == NULL) return MMSYSERR_INVALPARAM;
+    if (lpWaveOutHdr == NULL || uSize < sizeof (WAVEHDR))
+	return MMSYSERR_INVALPARAM;
 
     if ((wmld = MMDRV_Get(hWaveOut, MMDRV_WAVEOUT, FALSE)) == NULL)
 	return MMSYSERR_INVALHANDLE;
@@ -2625,6 +2626,9 @@
 
     TRACE("(%p, %p, %u);\n", hWaveOut, lpWaveOutHdr, uSize);
 
+    if (lpWaveOutHdr == NULL || uSize < sizeof (WAVEHDR))
+	return MMSYSERR_INVALPARAM;
+    
     if (!(lpWaveOutHdr->dwFlags & WHDR_PREPARED)) {
 	return MMSYSERR_NOERROR;
     }