diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_FCNTL_H.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_FCNTL_H.h
new file mode 100644
index 0000000..bb94506
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_FCNTL_H.h
@@ -0,0 +1,11 @@
+// HAVE_FCNTL_H
+
+#undef HAVE_FCNTL_H
+
+#if defined(__linux__)   || \
+    defined(__FreeBSD__) || \
+    defined(__OpenBSD__) || \
+    defined(__NetBSD__)  || \
+    (defined(__APPLE__) && defined(__MACH__))
+#  define HAVE_FCNTL_H 1
+#endif
diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_UNISTD_H.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_UNISTD_H.h
new file mode 100644
index 0000000..7d57a04
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_UNISTD_H.h
@@ -0,0 +1,11 @@
+// HAVE_UNISTD_H
+
+#undef HAVE_UNISTD_H
+
+#if defined(__linux__)   || \
+    defined(__FreeBSD__) || \
+    defined(__OpenBSD__) || \
+    defined(__NetBSD__)  || \
+    (defined(__APPLE__) && defined(__MACH__))
+#  define HAVE_UNISTD_H 1
+#endif