Postgres problem

Hello:

I am having problem interfacing the postgres database with the 
frontend(libpq),i.e using C.Database runs fine.
PROBLEMS ARE:           1)When compiling the C-program given in the             example for connecting the database to
the           frontend using      $gcc -I /home/guest/pgsql/include test.c       output:           /tmp/ccwWFbHo.o:In
function'exit_nicely':           /tmp/ccwWFbHo.o(.text+0x8):undefined referance to 'PQfinish'
/tmp/ccwWFbHo.o:Infunction 'main':           /tmp/ccwWFbHo.o(.text+0x66):undefined referance to
 
'PQsetdblogin'
/tmp/ccwWFbHo.o(.text+0x66):undefinedreferance to 'PQstatus'          
 

...............................................................                      2)When I want to use the command
         $createlang c (dbname)           OUTPUT:                  createlang:missing required argument PGLIB
directory.                                                     
 

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                        I shall be grateful if you reply giving me suggestion to solve           the problems.
  Thanking you 
  With regards     Simanchal           
  c/o Prof L M Patnaik