diff --git a/libs/port/spawn.c b/libs/port/spawn.c
index 38c2944..44d904e 100644
--- a/libs/port/spawn.c
+++ b/libs/port/spawn.c
@@ -32,6 +32,11 @@
 # include <unistd.h>
 #endif
 
+/* OpenBSD doesn't have ENOTSUP, but does have EOPNOTSUPP */
+#if defined (EOPNOTSUPP) && !defined (ENOTSUP)
+#define ENOTSUP EOPNOTSUPP
+#endif
+
 #ifndef HAVE_SPAWNVP
 int spawnvp(int mode, const char *cmdname, const char *const argv[])
 {