diff --git a/Makefile.rules b/Makefile.rules
index b1d1a49..30716dc 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -44,7 +44,7 @@ CXXFLAGS  = $(CFLAGS)
 LD        = ld
 SOLDFLAGS = -shared
 
-CFLAGS += -D_REENTRANT
+CFLAGS += -D_REENTRANT -D_FILE_OFFSET_BITS=64
 LDFLAGS += -lpthread
 
 ifdef DMALLOCLIB