-V and -b fail with gpc-20070904

[J. David Bryan]

Attempting to use an alternate installed gpc version or gpc compiled for a 
different machine does not work:

  $ gpc -V 4.1.2 a.pas
  gpc: `-V' must come at the start of the command line

  $ gpc -b m68k a.pas
  gpc: `-b' must come at the start of the command line

Problem appears to be that "init_gpc_options" inserts "-famtmpfile" and 
perhaps "-fsyntax-only" in front of all user-specified options, but 
"process_command" requires that "-V" and "-b" appear first.

Workaround is to call the desired compiler driver directly, e.g.:

  $ i686-pc-mingw32-gpc-4.1.2 a.pas

...although that is somewhat awkward.

Also, if the above bug is fixed, it appears that "process_command" will 
invoke "<machine>-gcc-<version>" instead of "<machine>-gpc-<version>".

                                      -- Dave