diff --git a/configure.ac b/configure.ac
index 78fa890fe..d07ec9b9a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -94,7 +94,7 @@ AC_SUBST([ABI_AGE])
 AM_CPPFLAGS="${AM_CPPFLAGS} -DIN_HAMLIB"
 
 # Add Hamlib header include paths
-AM_CPPFLAGS="${AM_CPPFLAGS} -I\$(top_srcdir)/include -I\$(top_srcdir)/src -I\$(top_srcdir)/lib -I\$(top_builddir)/include  -I\$(top_srcdir)/include/hamlib"
+AM_CPPFLAGS="${AM_CPPFLAGS} -I\$(top_srcdir)/include -I\$(top_srcdir)/src -I\$(top_srcdir)/lib -I\$(top_builddir)/include  -I\$(top_srcdir)/include/hamlib -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64"
 
 
 ## --------------- ##