Building avr-gcc - problems with directories

I am trying to package up an AVR tool chain again, but am unable to get
avr-gcc to run its own assembler instead of the host one.

Configuration (some of the configure options are superfluous):

unset LD_LIBRARY_PATH
export LD_LIBRARY_PATH
PATH=/sbin:/usr/sbin:/usr/local/sbin:/bin:/usr/bin:/usr/local/bin
export PATH
AVR_CFLAGS=[Some host-specific flags, with -m32/-m64 removed]
CFLAGS="$AVR_CFLAGS" \
../gcc-4.8.1/configure \
	-v \
	--prefix=/usr/avr \
	--exec-prefix=/usr/avr \
	--bindir=/usr/avr/bin \
	--libdir=/usr/avr/lib64 \
	--libexecdir=/usr/avr/lib64 \
	--mandir=/usr/avr/share/man \
	--infodir=/usr/avr/share/info \
	--with-gnu-ld \
	--with-gnu-as \
	--target=avr \
	--enable-languages="c,c++" \
	--program-prefix=avr- \
	--program-suffix=-481 \
	--disable-nls \
	--disable-libssp \
	--with-dwarf2 \
	--with-ppl \
	--with-cloog \

So prefix is /usr/avr. I figure /usr will never work for a cross
compiler because it clashes with the host's compiler's lib and include.

The problem is that avr-gcc always calls the assembler as "as", instead
of "avr-as" or using a full path. It shows when trying to compile
avr-libc.

Only avr-binutils are installed when building avr-gcc.

I am using avr-binutils 2.23 built (and maintained) by someone else, and
it's using a prefix of /usr. It installs avr-as, avr-ld etc into
/usr/bin.

The aim is to have avr-gcc etc in /usr/bin as well, though it's easy to
place some symlinks as needed.

One solution is to replace avr-gcc etc with wrapper scripts prep-ending
/usr/avr/bin, but the thought makes me wince.

I am using a program-suffix to be able to install multiple avr-gcc
versions in parallel. One of them will have a version-less symlink. I am
testing with 4.8.1.

Is it possible to achieve this at all? There seemed to have been fewer
problems with a prefix outside of /usr but I want to get away from that.

Thanks for any suggestions,

Volker

-- 
Volker Kuhlmann
http://volker.dnsalias.net/	Please do not CC list postings to me.