diff --git a/lib/process.cc b/lib/process.cc
index 32cf672..fc31194 100644
--- a/lib/process.cc
+++ b/lib/process.cc
@@ -203,7 +203,9 @@ namespace crucible {
 		NTOA_TABLE_ENTRY_ENUM(SIGLOST),
 #endif
 		NTOA_TABLE_ENTRY_ENUM(SIGWINCH),
+#ifdef SIGUNUSED
 		NTOA_TABLE_ENTRY_ENUM(SIGUNUSED),
+#endif
 
 		// realtime
 		NTOA_TABLE_ENTRY_ENUM(SIGRTMIN),