How to include needed C library using gcc?

Use the -l command line option. You can specify the library search path with the -L option. E.g:

gcc -o myprogram -lfoo -L/home/me/foo/lib myprogram.c

This will link myprogram with the static library libfoo.a in the folder /home/me/foo/lib.

-I<search path to include files>
-L<search path to the lib file>
-l<libname>