When configuring a s390->s390 or cris->cris crosscompiler

 (ok, I haven't hit this yet, but one of these days I'll get me an account

 on an s390, and then I'll need this patch :-), you'll get the

 following error:

 + /build/s390-unknown-linux-gnu/gcc-3.3-glibc-2.3.2/gcc-3.3/configure

 --target=s390-unknown-linux-gnu --host=s390-host_unknown-linux-gnu

 --prefix=/result/s390-unknown-linux-gnu/gcc-3.3-glibc-2.3.2

 --enable-languages=c

 --with-local-prefix=/result/s390-unknown-linux-gnu/gcc-3.3-glibc-2.3.2/s390-

 unknown-linux-gnu --enable-threads=no --without-headers --with-newlib

 --disable-shared

 ...

 *** --with-headers is only supported when cross compiling

 This error pops up only when you're using Daniel Jacobowitz's technique

 of slightly changing the target and host tuples to make them different

 enough to force gcc's build system to not try to pull in system libraries

 or headers.  This technique is needed e.g. to build an x86 -> x86

 cross-compiler.

 (The LFS developers ran into the same bug that prompted me to use

 this technique; they point people who run into it to

 http://linuxfromscratch.org/~greg/pure_lfs.txt, which is a different

 way of avoiding this problem.  I think the tuple tweak is the way to go, though.)

 config-patches@gnu.org rejected this patch, on the grounds that there

 is only one vendor of each of those two architectures, so the 

 canonicalization is by definition correct.  When I pointed out the

 difficulty this causes for people building s390 -> s390 or

 cris -> cris compilers that are incompatible with the system

 libraries and thus must be built like cross-compilers, he grumped and said 

 "autoconf should let you specify a cross-compiler in some other way than

 comparing tuple strings".

 --- gcc-3.3/config.sub.old	Sun Jun  8 20:38:47 2003

 +++ gcc-3.3/config.sub	Sun Jun  8 20:40:34 2003

 @@ -433,9 +433,12 @@

  	crds | unos)

  		basic_machine=m68k-crds

  		;;

 -	cris | cris-* | etrax*)

 +	cris | etrax*)

  		basic_machine=cris-axis

  		;;

 +	cris-*)

 +		basic_machine=cris-`echo $basic_machine | sed 's/^[^-]*-//'`

 +		;;

  	da30 | da30-*)

  		basic_machine=m68k-da30

  		;;

 @@ -820,11 +823,17 @@

  	rtpc | rtpc-*)

  		basic_machine=romp-ibm

  		;;

 -	s390 | s390-*)

 +	s390)

  		basic_machine=s390-ibm

  		;;

 -	s390x | s390x-*)

 +	s390-*)

 +		basic_machine=s390-`echo $basic_machine | sed 's/^[^-]*-//'`

 +		;;

 +	s390x)

  		basic_machine=s390x-ibm

 +		;;

 +	s390x-*)

 +		basic_machine=s390x-`echo $basic_machine | sed 's/^[^-]*-//'`

  		;;

  	sa29200)

  		basic_machine=a29k-amd