<values.h> is a non-standard legacy header not present on OpenBSD; use
the POSIX-standard <float.h> instead.

Index: libweston/input.c
--- libweston/input.c.orig
+++ libweston/input.c
@@ -34,7 +34,7 @@
 #include <sys/mman.h>
 #include <assert.h>
 #include <unistd.h>
-#include <values.h>
+#include <float.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <errno.h>
