Move some bitmap logic out of bitmapset.c

Move the logic for selecting appropriate pg_bitutils.h
functions based on word size to bitmapset.h for wider
visibility.

Reviewed (in a previous version) by Tom Lane
Discussion: https://postgr.es/m/CAFBsxsFW2JjTo58jtDB%2B3sZhxMx3t-3evew8%3DAcr%2BGGhC%2BkFaA%40mail.gmail.com

Author: j-naylor

src/backend/nodes/bitmapset.c

@@ -71,19 +71,6 @@
 
 #define HAS_MULTIPLE_ONES(x)	((bitmapword) RIGHTMOST_ONE(x) != (x))
 
-/* Select appropriate bit-twiddling functions for bitmap word size */
-#if BITS_PER_BITMAPWORD == 32
-#define bmw_leftmost_one_pos(w)		pg_leftmost_one_pos32(w)
-#define bmw_rightmost_one_pos(w)	pg_rightmost_one_pos32(w)
-#define bmw_popcount(w)				pg_popcount32(w)
-#elif BITS_PER_BITMAPWORD == 64
-#define bmw_leftmost_one_pos(w)		pg_leftmost_one_pos64(w)
-#define bmw_rightmost_one_pos(w)	pg_rightmost_one_pos64(w)
-#define bmw_popcount(w)				pg_popcount64(w)
-#else
-#error "invalid BITS_PER_BITMAPWORD"
-#endif
-
 #ifdef USE_ASSERT_CHECKING
 /*
  * bms_is_valid_set - for cassert builds to check for valid sets

src/include/nodes/bitmapset.h

@@ -73,6 +73,19 @@ typedef enum
 	BMS_MULTIPLE,				/* >1 member */
 } BMS_Membership;
 
+/* Select appropriate bit-twiddling functions for bitmap word size */
+#if BITS_PER_BITMAPWORD == 32
+#define bmw_leftmost_one_pos(w)		pg_leftmost_one_pos32(w)
+#define bmw_rightmost_one_pos(w)	pg_rightmost_one_pos32(w)
+#define bmw_popcount(w)				pg_popcount32(w)
+#elif BITS_PER_BITMAPWORD == 64
+#define bmw_leftmost_one_pos(w)		pg_leftmost_one_pos64(w)
+#define bmw_rightmost_one_pos(w)	pg_rightmost_one_pos64(w)
+#define bmw_popcount(w)				pg_popcount64(w)
+#else
+#error "invalid BITS_PER_BITMAPWORD"
+#endif
+
 
 /*
  * function prototypes in nodes/bitmapset.c