diff --git a/libdm/dm-tools/util.h b/libdm/dm-tools/util.h
index 730b90370..3925a7438 100644
--- a/libdm/dm-tools/util.h
+++ b/libdm/dm-tools/util.h
@@ -76,4 +76,45 @@
 
 #define FMTVGID "%." DM_TO_STRING(ID_LEN) "s"
 
+/*
+ * GCC 3.4 adds a __builtin_clz, which uses the count leading zeros (clz)
+ * instruction on arches that have one. Provide a fallback using shifts
+ * and comparisons for older compilers.
+ */
+#ifdef HAVE___BUILTIN_CLZ
+#define clz(x) __builtin_clz((x))
+#else /* ifdef HAVE___BUILTIN_CLZ */
+static unsigned _dm_clz(unsigned x)
+{
+	int n;
+
+	if ((int)x <= 0) return (~x >> 26) & 32;
+
+	n = 1;
+
+	if ((x >> 16) == 0) {
+		n = n + 16;
+		x = x << 16;
+	}
+
+	if ((x >> 24) == 0) {
+		n = n + 8;
+		x = x << 8;
+	}
+
+	if ((x >> 28) == 0) {
+		n = n + 4;
+		x = x << 4;
+	}
+
+	if ((x >> 30) == 0) {
+		n = n + 2;
+		x = x << 2;
+	}
+	n = n - (x >> 31);
+	return n;
+}
+#define clz(x) _dm_clz((x))
+#endif /* ifdef HAVE___BUILTIN_CLZ */
+
 #endif
diff --git a/libdm/misc/dmlib.h b/libdm/misc/dmlib.h
index 22328696b..85a22c50f 100644
--- a/libdm/misc/dmlib.h
+++ b/libdm/misc/dmlib.h
@@ -72,7 +72,7 @@
 #define DM_EXPORT_SYMBOL_BASE(func)
 #endif
 
-#include "lib/misc/util.h"
+#include "libdm/dm-tools/util.h"
 
 #include "libdm/libdevmapper.h"
 #include "libdm/misc/dm-logging.h"