You need 2 directories in tmp (and do not use /tmp !) !
The GCC documentation recommends building GCC
outside of the source directory in a dedicated
../gcc-4.1.2/configure .. :
The 2 dots ../ means : look or go outside
this directory (will take you to tmp)
Example with ../../ => then you would be
I think the LFS text is pretty clear about
the build directory, you might want to read
it over some more times.
Also remember not to reuse tmp/gcc-4.1.2
and the build dir for the next chapter
(see text, LFS) .. create new ones.
And please refer LFS version and chapter
if you have further questions.
Good Luck !