diff --git a/src/libthread/FreeBSD.c b/src/libthread/FreeBSD.c
index 46c1b05f..d80aaec9 100644
--- a/src/libthread/FreeBSD.c
+++ b/src/libthread/FreeBSD.c
@@ -1,5 +1,8 @@
 #include "threadimpl.h"
 
+#undef exits
+#undef _exits
+
 extern int __isthreaded;
 
 /*
diff --git a/src/libthread/Linux.c b/src/libthread/Linux.c
index 25a98d96..f741a03d 100644
--- a/src/libthread/Linux.c
+++ b/src/libthread/Linux.c
@@ -1,5 +1,8 @@
 #include "threadimpl.h"
 
+#undef exits
+#undef _exits
+
 static int
 timefmt(Fmt *fmt)
 {