--- coregrind/pub_core_trampoline.h.orig
+++ coregrind/pub_core_trampoline.h
@@ -64,6 +64,14 @@
 extern void VG_(amd64_freebsd_SUBST_FOR_sigreturn);
 #endif
 
+#if defined(VGP_x86_openbsd)
+extern void VG_(x86_openbsd_SUBST_FOR_sigreturn);
+#endif
+
+#if defined(VGP_amd64_openbsd)
+extern void VG_(amd64_openbsd_SUBST_FOR_sigreturn);
+#endif
+
 #if defined(VGP_x86_linux)
 extern Addr VG_(x86_linux_SUBST_FOR_sigreturn);
 extern Addr VG_(x86_linux_SUBST_FOR_rt_sigreturn);
