Further correction: on reflection, after examining all the call

sites for uint64_make(), we _shouldn't_ attempt to preserve high
bits in the low-order argument; it turns out not to be what the call
sites want.

[originally from svn r8185]

int64.c

@@ -49,7 +49,7 @@ void uint64_decimal(uint64 x, char *buffer)
 uint64 uint64_make(unsigned long hi, unsigned long lo)
 {
     uint64 y;
-    y.hi = (hi + (lo >> 32)) & 0xFFFFFFFFU;
+    y.hi = hi & 0xFFFFFFFFU;
     y.lo = lo & 0xFFFFFFFFU;
     return y;
 }