4.2 Project: "@file" support

[Joern RENNECKE]

 > applications will just work, but introducing the very serious risk of
 > security problems, leading to, say:
 >
 > gcc: dj:yourpassword:1234:567:DJ: invalid argument
 >
 > instead of
 >
 > gcc: @/etc/passwd: invalid argument

If you want to use gcc to read a file, you get a closer likeness
to the data with:

gcc -E -C -x c /etc/passwd

Polluting argument name space seems more worrying.  A long option would 
not create
such ambiguities.