You cannot build GNU CC (or GNU Pascal) by itself on MS-DOS; it will not compile under any MS-DOS compiler except itself. The official MS-DOS port of GCC is called djgpp, and it is available from `simtel.coast.net' and it has mirrors all over the world. The `configure' script is replaced by an MS-DOS batch file called `configure.bat' wich does essentially the same. Detailed instructions are in the file `config/msdos/README.dj' of the GNU Pascal source distribution.