CCL:"ETIME" command in LINUX (f77)



     I have installed LINUX on my pentium in order to run some
 molecular dinamics writen in FORTRAN for unix. When I tryed to
 compile the programs I have found that it uses external function
 ETIME ( for cpu run time) but on LINUX that function doesnt seem to
 exist.
          During my investigation of a problem I have found up that
 LINUX doesnt realy have a f77 compiler. All it has is F77 script that
 uses f2c translator to compile F-programs. After searching some ftp
 sites I have come up with an f77.c file BUT in that ftp site there
 were no proper headers to compile it ( I mean  .h files) so it turned
 out to be useless.
      I would be very gratefull if any of you could help me with one
 of the following problems:
    1. What is LINUX'es external function for reading the CPU time in
 fortran ( i.e. ETIME)
     2. Where could I find an f77.c together with all needed headers
 to compile it on LINUX.
 thank you in advance Igor Derzy.