Check architecture bit width is consistent with Postgres

src/bitutils.h

@@ -8,6 +8,9 @@
 #error "Requires PostgreSQL 13+"
 #endif
 
+/* Check architecture in first header */
+StaticAssertDecl(sizeof(Datum) == SIZEOF_DATUM, "Architecture mismatch");
+
 extern uint64 (*BitHammingDistance) (uint32 bytes, unsigned char *ax, unsigned char *bx, uint64 distance);
 extern double (*BitJaccardDistance) (uint32 bytes, unsigned char *ax, unsigned char *bx, uint64 ab, uint64 aa, uint64 bb);