diff -r 000000000000 -r 6474c204b198 memory/jemalloc/src/include/msvc_compat/strings.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/memory/jemalloc/src/include/msvc_compat/strings.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+#ifndef strings_h
+#define strings_h
+
+/* MSVC doesn't define ffs/ffsl. This dummy strings.h header is provided
+ * for both */
+#include <intrin.h>
+#pragma intrinsic(_BitScanForward)
+static __forceinline int ffsl(long x)
+{
+	unsigned long i;
+
+	if (_BitScanForward(&i, x))
+		return (i + 1);
+	return (0);
+}
+
+static __forceinline int ffs(int x)
+{
+
+	return (ffsl(x));
+}
+
+#endif