A few fixes in ExtSelectClipRgn metafile functions.

diff --git a/dlls/gdi/enhmfdrv/dc.c b/dlls/gdi/enhmfdrv/dc.c
index 43ca973..d6fd632 100644
--- a/dlls/gdi/enhmfdrv/dc.c
+++ b/dlls/gdi/enhmfdrv/dc.c
@@ -134,11 +134,16 @@
     DWORD size, rgnsize;
     BOOL ret;
 
-    rgnsize = GetRegionData( hrgn, 0, NULL );
-    size = rgnsize + sizeof(*emr) - 1;
-    emr = HeapAlloc( GetProcessHeap(), 0, size );
+    if (!hrgn)
+    {
+        if (mode != RGN_COPY) return ERROR;
+        rgnsize = 0;
+    }
+    else rgnsize = GetRegionData( hrgn, 0, NULL );
 
-    GetRegionData( hrgn, rgnsize, (RGNDATA *)&emr->RgnData );
+    size = rgnsize + offsetof(EMREXTSELECTCLIPRGN,RgnData);
+    emr = HeapAlloc( GetProcessHeap(), 0, size );
+    if (rgnsize) GetRegionData( hrgn, rgnsize, (RGNDATA *)&emr->RgnData );
 
     emr->emr.iType = EMR_EXTSELECTCLIPRGN;
     emr->emr.nSize = size;
diff --git a/dlls/gdi/enhmfdrv/graphics.c b/dlls/gdi/enhmfdrv/graphics.c
index 402beaa..997f3ab 100644
--- a/dlls/gdi/enhmfdrv/graphics.c
+++ b/dlls/gdi/enhmfdrv/graphics.c
@@ -490,7 +490,7 @@
     if(!index) return FALSE;
 
     rgnsize = GetRegionData( hrgn, 0, NULL );
-    size = rgnsize + sizeof(EMRFILLRGN) - 1;
+    size = rgnsize + offsetof(EMRFILLRGN,RgnData);
     emr = HeapAlloc( GetProcessHeap(), 0, size );
 
     GetRegionData( hrgn, rgnsize, (RGNDATA *)&emr->RgnData );
@@ -523,7 +523,7 @@
     if(!index) return FALSE;
 
     rgnsize = GetRegionData( hrgn, 0, NULL );
-    size = rgnsize + sizeof(EMRFRAMERGN) - 1;
+    size = rgnsize + offsetof(EMRFRAMERGN,RgnData);
     emr = HeapAlloc( GetProcessHeap(), 0, size );
 
     GetRegionData( hrgn, rgnsize, (RGNDATA *)&emr->RgnData );
@@ -559,7 +559,7 @@
 
 
     rgnsize = GetRegionData( hrgn, 0, NULL );
-    size = rgnsize + sizeof(EMRINVERTRGN) - 1;
+    size = rgnsize + offsetof(EMRINVERTRGN,RgnData);
     emr = HeapAlloc( GetProcessHeap(), 0, size );
 
     GetRegionData( hrgn, rgnsize, (RGNDATA *)&emr->RgnData );
diff --git a/dlls/gdi/mfdrv/graphics.c b/dlls/gdi/mfdrv/graphics.c
index aa27b6b..54c4ad3 100644
--- a/dlls/gdi/mfdrv/graphics.c
+++ b/dlls/gdi/mfdrv/graphics.c
@@ -237,7 +237,7 @@
     WORD *Param, *StartBand;
     BOOL ret;
 
-    len = GetRegionData( hrgn, 0, NULL );
+    if (!(len = GetRegionData( hrgn, 0, NULL ))) return -1;
     if( !(rgndata = HeapAlloc( GetProcessHeap(), 0, len )) ) {
         WARN("Can't alloc rgndata buffer\n");
 	return -1;
@@ -376,16 +376,15 @@
 INT MFDRV_ExtSelectClipRgn( PHYSDEV dev, HRGN hrgn, INT mode )
 {
     INT16 iRgn;
+    INT ret;
 
-    if (mode != RGN_COPY)
-    {
-        FIXME( "mode %d not supported\n", mode );
-        return ERROR;
-    }
+    if (mode != RGN_COPY) return ERROR;
+    if (!hrgn) return NULLREGION;
     iRgn = MFDRV_CreateRegion( dev, hrgn );
-    if(iRgn == -1)
-        return ERROR;
-    return MFDRV_MetaParam1( dev, META_SELECTCLIPREGION, iRgn ) ? SIMPLEREGION : ERROR;
+    if(iRgn == -1) return ERROR;
+    ret = MFDRV_MetaParam1( dev, META_SELECTCLIPREGION, iRgn ) ? NULLREGION : ERROR;
+    MFDRV_MetaParam1( dev, META_DELETEOBJECT, iRgn );
+    return ret;
 }