diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_BZERO.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_BZERO.h
new file mode 100644
index 0000000..8f360ae
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_BZERO.h
@@ -0,0 +1,12 @@
+// HAVE_EXPLICIT_BZERO
+
+#undef HAVE_EXPLICIT_BZERO
+
+/* Since FreeBSD 11, OpenBSD 5.5, and glibc 2.25.
+ */
+#if (defined(__FreeBSD__) && __FreeBSD__ >= 11) ||                      \
+    (defined(__OpenBSD__) && defined(OpenBSD) && OpenBSD >= 201405) ||  \
+    (defined(__GLIBC__) && defined(__GLIBC_MINOR__) &&                  \
+     (__GLIBC__ > 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ >= 25))
+#  define HAVE_EXPLICIT_BZERO 1
+#endif
diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_MEMSET.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_MEMSET.h
new file mode 100644
index 0000000..424238e
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_EXPLICIT_MEMSET.h
@@ -0,0 +1,9 @@
+// HAVE_EXPLICIT_MEMSET
+
+#undef HAVE_EXPLICIT_MEMSET
+
+/* Since NetBSD 7.0.0.
+ */
+#if defined(__NetBSD_Version__) && __NetBSD_Version__ >= 700000000
+#  define HAVE_EXPLICIT_MEMSET 1
+#endif