strange result when compiling w/ -fpreprocessed but w/out -fdumpbase

[Joern RENNECKE <joern dot rennecke at st dot com>]

When you compile a file that contains a line directive, e.g.:

# 1 "../../libgcc2.c"
int f ()
{
 return 0;
}

using the -fpreprocessed option to cc1, but without -fdumpbase, the base 
filename of the
line number directive us used both for the assembly output file and for 
debugging dumps
from -da.  This can be rather confusing when you can't find neither 
output file nor debugging
dumps in the current directory.  And at the least, the -fpreprocessed 
documentation is wrong
when it states that this option is implicit when the file ends in .i; 
this effect of -fpreprocesed
only appears when the option is actually passed to cc1.