Strange build error on PPC OS X 10.4

[xorquewasp@googlemail.com]

I'm encountering a very strange error trying to build GCC 4.2.3 as
a cross compiler on OS X 10.4 PPC:

make GCC_FOR_TARGET="/dev-share/src/build-gcc/./gcc/xgcc -B/dev-share/src/build-gcc/./gcc/ -B/usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/bin/ -B/usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/lib/ -isystem /usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/include -isystem /usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/sys-include" \
  AR_FOR_TARGET="i386-apple-darwin-ar" \
  AR_CREATE_FOR_TARGET="i386-apple-darwin-ar  rc" \
  AR_EXTRACT_FOR_TARGET="i386-apple-darwin-ar  x" \
  AR_FLAGS_FOR_TARGET="" \
  CC="gcc" CFLAGS="-g -O2 -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Wold-style-definition -Wmissing-format-attribute  " \
  BUILD_PREFIX="" \
  BUILD_PREFIX_1="" \
  LANGUAGES="" \
  LIBGCC2_CFLAGS="-O2  -O2 -g -O2  -DIN_GCC    -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -fPIC -pipe -g -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED  "  \
  MULTILIB_CFLAGS="" T= crt3.o
/dev-share/src/build-gcc/./gcc/xgcc -B/dev-share/src/build-gcc/./gcc/ -B/usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/bin/ -B/usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/lib/ -isystem /usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/include -isystem /usr/local/gcc-4.2.3-x-i386/i386-apple-darwin/sys-include -O2 -g -O2  -DIN_GCC    -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -I. -I. -I../../gcc-4.2.3/gcc -I../../gcc-4.2.3/gcc/. -I../../gcc-4.2.3/gcc/../include -I./../intl -I../../gcc-4.2.3/gcc/../libcpp/include  -I../../gcc-4.2.3/gcc/../libdecnumber -I../libdecnumber  \
  -fno-tree-dominator-opts  \
  -c ../../gcc-4.2.3/gcc/config/darwin-crt3.c -o crt3.o
/dev-share/src/build-gcc/./gcc/as: line 2: exec: i386: not found
make[4]: *** [crt3.o] Error 1
make[3]: *** [extra] Error 2
make[2]: *** [stmp-multilib] Error 2
make[1]: *** [all-gcc] Error 2
make: *** [all] Error 2

I'm not sure if I'm supposed to do something before the build of
gcc on OS X, but I'm pretty certain that $objdir/gcc/as isn't supposed
to look like this:

$ cat gcc/as 
#!/bin/sh
exec  "$@"

The other temporary 'binutils' look the same:

$ cat gcc/nm 
#!/bin/sh
exec  "$@"

What could be causing these files to be incorrectly generated?

The complete build steps I'm using are simply:

$ export TARGET=i386-apple-darwin
$ export PREFIX=/usr/local/gcc-4.2.3-x-i386
$ export PATH=$PATH:$PREFIX/bin
$ cd build-gcc
$ ../gcc-4.2.3/configure --disable-libssp --disable-gomp --target=$TARGET \
  --prefix=$PREFIX --enable-languages=c,ada
$ make

Any help would be appreciated.