diff --git a/libsrc/mmapio.c b/libsrc/mmapio.c
index 98b9ddb..8a27946 100644
--- a/libsrc/mmapio.c
+++ b/libsrc/mmapio.c
@@ -44,7 +44,7 @@
 
 #ifdef HAVE_MREMAP
   /* This is conditionalized by __USE_GNU ; why? */
-  extern void *mremap(void*,size_t,size_t,int);
+  extern void *mremap(void*,size_t,size_t,int,...);
 # ifndef MREMAP_MAYMOVE
 #   define MREMAP_MAYMOVE 1
 # endif