diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZ.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZ.h
new file mode 100644
index 0000000..0010d96
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZ.h
@@ -0,0 +1,10 @@
+// HAVE_BUILTIN_CTZ
+
+#undef HAVE_BUILTIN_CTZ
+
+/* __builtin_ctz (count the leading/most-significant zeros in an unsigned int)
+ * is available in all versions of GCC and Clang.
+ */
+#if defined (__GNUC__) || defined(__clang__)
+#  define HAVE_BUILTIN_CTZ 1
+#endif
diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZL.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZL.h
new file mode 100644
index 0000000..88b26a2
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZL.h
@@ -0,0 +1,10 @@
+// HAVE_BUILTIN_CTZL
+
+#undef HAVE_BUILTIN_CTZL
+
+/* __builtin_ctzl (count the leading/most-significant zeros in an unsigned
+ * long) is available in all versions of GCC and Clang.
+ */
+#if defined (__GNUC__) || defined(__clang__)
+#  define HAVE_BUILTIN_CTZL 1
+#endif
diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZLL.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZLL.h
new file mode 100644
index 0000000..693e380
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_BUILTIN_CTZLL.h
@@ -0,0 +1,10 @@
+// HAVE_BUILTIN_CTZLL
+
+#undef HAVE_BUILTIN_CTZLL
+
+/* __builtin_ctzll (count the leading/most-significant zeros in an unsigned
+ * long long) is available in all versions of GCC and Clang.
+ */
+#if defined (__GNUC__) || defined(__clang__)
+#  define HAVE_BUILTIN_CTZLL 1
+#endif