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Be more careful with type of left operand of <<

On a 32-bit system, evaluating 1<<31 causes undefined behaviour because
1 is signed and so it produces signed overflow.  UBSan has spotted a
couple of occasions where this happens in Puzzles, so in each case I've
converted the left operand to the unsigned result type we actually want.

--- a/cube.c

+++ b/cube.c

@@ -202,8 +202,8 @@

 };

 #define SET_SQUARE(state, i, val) \

-    ((state)->bluemask[(i)/32] &= ~(1 << ((i)%32)), \

-     (state)->bluemask[(i)/32] |= ((!!val) << ((i)%32)))

+    ((state)->bluemask[(i)/32] &= ~(1UL << ((i)%32)), \

+     (state)->bluemask[(i)/32] |= ((unsigned long)(!!val) << ((i)%32)))

 #define GET_SQUARE(state, i) \

     (((state)->bluemask[(i)/32] >> ((i)%32)) & 1)

--- a/random.c

+++ b/random.c

@@ -254,12 +254,12 @@

     }

     /*

-     * `(1 << bits) - 1' is not good enough, since if bits==32 on a

+     * `(1UL << bits) - 1' is not good enough, since if bits==32 on a

      * 32-bit machine, behaviour is undefined and Intel has a nasty

      * habit of shifting left by zero instead. We'll shift by

      * bits-1 and then separately shift by one.

      */

-    ret &= (1 << (bits-1)) * 2 - 1;

+    ret &= (1UL << (bits-1)) * 2 - 1;

     return ret;

 }