diff --git a/lib/strtoimax.c b/lib/strtoimax.c
index c9bd2ad..f190322 100644
--- a/lib/strtoimax.c
+++ b/lib/strtoimax.c
@@ -45,6 +45,9 @@ long long int strtoll (char const *, char **, int);
 # endif
 #endif
 
+#undef strtoimax
+#undef strtoumax
+
 #ifdef UNSIGNED
 # define Have_long_long HAVE_UNSIGNED_LONG_LONG_INT
 # define Int uintmax_t