+dnl Check for stuff needed for building the GiNaC interactive shell (ginsh):
+AC_CHECK_HEADERS(unistd.h)
+AC_CHECK_HEADERS(readline/readline.h readline/history.h)
+save_LIBS=$LIBS
+AC_CHECK_LIB(readline, readline)
+GINSH_LIBS=$LIBS
+LIBS=$save_LIBS
+AC_SUBST(GINSH_LIBS)
+