--- ./include/tables_contained_in.h_orig	2020-07-21 11:55:35 +0000
+++ ./include/tables_contained_in.h	2020-07-21 11:56:25 +0000
@@ -34,6 +34,18 @@
 #pragma intrinsic(_BitScanForward64)
 #endif
 
+int
+ffsll(long long mask)
+{
+	int bit;
+
+	if (mask == 0)
+		return (0);
+	for (bit = 1; !(mask & 1); bit++)
+		mask = (unsigned long long)mask >> 1;
+	return (bit);
+}
+
 // A utility class to loop over all set bits in the given map.
 // Use as:
 //