--- a/configure.ac
+++ b/configure.ac
@@ -73,7 +73,6 @@
 BOOST_PROGRAM_OPTIONS
 BOOST_IOSTREAMS
 BOOST_FILESYSTEM
-BOOST_SYSTEM
 
 # Checks for header files.
 AC_CHECK_HEADERS([sys/ioctl.h unistd.h sys/types.h sys/stat.h signal.h])