--- a/configure.ac
+++ b/configure.ac
@@ -34,7 +34,6 @@
 # Checks for libraries.
 AX_PATH_GENERIC([sdl2],,,, AC_MSG_ERROR([Could not find SDL2 (required).]))
 AX_BOOST_BASE(,, AC_MSG_ERROR([Could not find Boost (required).]))
-AX_BOOST_SYSTEM
 AX_BOOST_FILESYSTEM
 
 # Checks for header files.
--- a/Makefile.am
+++ b/Makefile.am
@@ -48,7 +48,7 @@
 if APP_BUNDLE
 quadra_LDFLAGS = $(AM_LDFLAGS) -rpath @executable_path/../Frameworks
 endif
-quadra_LDADD = $(SDL2_LIBS) $(BOOST_FILESYSTEM_LIB) $(BOOST_SYSTEM_LIB)
+quadra_LDADD = $(SDL2_LIBS) $(BOOST_FILESYSTEM_LIB)
 quadra_SOURCES = \
 	source/attack.h \
 	source/bitmap.cc \