To build type:

  perl Makefile.PL
  make
  make install

MapScript requires Swig version 1.3+. If you must re-SWIG things use a command like:

  swig -perl5 -shadow -outdir . -o mapscript_wrap.c ../mapscript.i

and then follow the sequence of steps to install mapscript. 

If you need to change the name of the mapscript module (default=mapscript) you need to:

  1) edit ../mapscript.i and change the name of the swig module
  2) edit Makefile.PL and edit the name 'mapscript' in the WriteMakefile subroutine call
  3) edit plmodule.i and change the name 'mapscript' to whatever the new name
     will be throughout the file

and now build as normal.