informix esql c在linux 9上编译问题！！！！！！！！

Question

esql -o demo1 demo1.ec
/opt/informix/lib/esql/libifgls.so: undefined reference to `__ctype_b'
/opt/informix/lib/esql/libifgls.so: undefined reference to `__ctype_toupper'
/opt/informix/lib/esql/libifgls.so: undefined reference to `__ctype_tolower'
collect2: ld returned 1 exit status

怎么找这几个库函数呢？