Make nsUUIDGenerator use the low bits, not the high ones, so we actually get

random numbers on 64-bit systems.  Bug 335549, r=vlad, sr=roc


git-svn-id: svn://10.0.0.236/trunk@199951 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/base/nsUUIDGenerator.cpp

@@ -152,7 +152,9 @@ nsUUIDGenerator::GenerateUUIDInPlace(nsID* id)
         long rval = random();
 
         PRUint8 *src = (PRUint8*)&rval;
-#ifdef IS_LITTLE_ENDIAN
+        // We want to grab the mRBytes least significant bytes of rval, since
+        // mRBytes less than sizeof(rval) means the high bytes are 0.
+#ifdef IS_BIG_ENDIAN
         src += sizeof(rval) - mRBytes;
 #endif
         PRUint8 *dst = ((PRUint8*) id) + (sizeof(nsID) - bytesLeft);