Fix assumption that ebx is caller-saved

"ebx" cannot be used without first pushing its value to the stack and
restoring it later, so just push the old value of "dest" to the stack
before "lock cmpxchg" and pop it into "eax" before returning.

wrappers/kernel32.c

@@ -165,9 +165,9 @@ __declspec(naked) LONG WINAPI CORKEL32_InterlockedCompareExchange(LONG* dest, LO
     mov edx, DWORD PTR [esp + 4] ; dest
     mov ecx, DWORD PTR [esp + 8] ; exchange
     mov eax, DWORD PTR [esp + 12] ; compare
-    mov ebx, DWORD PTR [edx]
+    push DWORD PTR [edx]
     lock cmpxchg DWORD PTR [edx], ecx
-    mov eax, ebx
+    pop eax
     ret 12
 
   ICE_is_386: