hooks not working in postgresql 9.3 (building from source)

hi,

I need to use the hook feature of planner in postgresql 9.3 to perform a
task. I am building postgresql from source.
To start with, I wanted to know how to create a hook and attach that shared
libray to postgresql. Hence i tried the examples given in "
wiki.postgresql.org/images/e/e3/Hooks_in_postgresql.pdf" and
"
https://github.com/gleu/Hooks-in-PostgreSQL/tree/master/examples/my_client_auth
".

I have copied the "my_client_auth.c" file and Makefile into
contrib/client_auth folder. make and make install is working fine.
This is the output of make install.

/bin/mkdir -p '/home/rajmohan/projects/lib/postgresql'
/usr/bin/install -c -m 755 my_client_auth.so
'/home/rajmohan/projects/lib/postgresql/'

after that i have added shared_preload_libraries = 'my_client_auth' to
postgresql.conf

Then i added the line
ClientAuthentication_hook_type client_auth_hook = NULL; at the top of a
file say planner.c in postgresql code
and inside a method im checking client_auth_hook value. When i rebuild and
run the project,
client_auth_hook value is always zero. It seems my_client_auth.so file is
not linked properly to my postgresql project.
Am i missing any step? how to access methods in my_client_auth.so from
postgresql. Kindly help