The following error occurs when attempting to build libgcc with the following
sequence of commands.

    setenv PREFIX "$HOME/cross-compiler/pdp11-gcc10.2.0"
    setenv PATH "$PREFIX/bin:$PATH"
    setenv TARGET pdp11-aout

    cd $HOME/cross-compiler/pdp11-gcc10.2.0
    mkdir workdir-binutils
    mkdir workdir-gcc

	cd $HOME/cross-compiler/pdp11-gcc10.2.0
    tar xzf binutils-2.35.1.tar.gz
    cd workdir-binutils

    ../binutils-2.35.1/configure --target=$TARGET --prefix="$PREFIX" \
            --with-sysroot --disable-nls --disable-werror
    gmake
    gmake install

    cd $HOME/cross-compiler/pdp11-gcc10.2.0
    tar xzf gcc-10.2.0.tar.gz
    cd gcc-10.2.0
    ./contrib/download-prerequisites
    cd ../workdir-gcc

    ../gcc-10.2.0/configure --target=$TARGET --prefix="$PREFIX" \
            --disable-nls --enable-languages=c --without-headers \
            --with-gnu-as --with-gnu-ld --disable-libssp
    gmake all-gcc
    gmake all-target-libgcc

================================================================================

Checking multilib configuration for libgcc...
gmake[2]: Entering directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/libgcc'
# If this is the top-level multilib, build all the other
# multilibs.
gmake[3]: Entering directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/libgcc'
if [ -z "msoft-float" ]; then \
  true; \
else \
  rootpre=`${PWDCMD-pwd}`/; export rootpre; \
  srcrootpre=`cd ../../../gcc-9.3.0/libgcc; ${PWDCMD-pwd}`/; export srcrootpre; \
  lib=`echo "${rootpre}" | sed -e 's,^.*/\([^/][^/]*\)/$,\1,'`; \
  compiler="/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/./gcc/xgcc -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/./gcc/ -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/bin/ -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/lib/ -isystem /home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/include -isystem /home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/sys-include   "; \
  for i in `${compiler} --print-multi-lib 2>/dev/null`; do \
    dir=`echo $i | sed -e 's/;.*$//'`; \
    if [ "${dir}" = "." ]; then \
      true; \
    else \
      if [ -d ../${dir}/${lib} ]; then \
        flags=`echo $i | sed -e 's/^[^;]*;//' -e 's/@/ -/g'`; \
        if (cd ../${dir}/${lib}; gmake "AR=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/bin/ar" "AR_FLAGS=rc" "CC=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/./gcc/xgcc -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/./gcc/ -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/bin/ -B/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/lib/
-isystem /home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/include -isystem /home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/sys-include   " "CFLAGS=-g -O2" "DESTDIR=" "EXTRA_OFILES=" "HDEFINES=" "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 644" "INSTALL_PROGRAM=/usr/bin/install -c" "LDFLAGS=" "LOADLIBES=" "RANLIB=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/bin/ranlib" "SHELL=/bin/sh" "prefix=/home/ataylor/cross-compiler/pdp11-gcc9.3.0" "exec_prefix=/home/ataylor/cross-compiler/pdp11-gcc9.3.0" "libdir=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/lib" "libsubdir=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/lib/gcc/pdp11-aout/9.3.0" "tooldir=/home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout" \
                        CFLAGS="-g -O2 ${flags}" \
                        CCASFLAGS=" ${flags}" \
                        FCFLAGS=" ${flags}" \
                        FFLAGS=" ${flags}" \
                        ADAFLAGS=" ${flags}" \
                        prefix="/home/ataylor/cross-compiler/pdp11-gcc9.3.0" \
                        exec_prefix="/home/ataylor/cross-compiler/pdp11-gcc9.3.0" \
                        GOCFLAGS="-O2 -g ${flags}" \
                        GDCFLAGS="-O2 -g ${flags}" \
                        CXXFLAGS="-g -O2 ${flags}" \
                        LIBCFLAGS="-g -O2 ${flags}" \
                        LIBCXXFLAGS="-g -O2 -fno-implicit-templates ${flags}" \
                        LDFLAGS=" ${flags}" \
                        MULTIFLAGS="${flags}" \
                        DESTDIR="" \
                        INSTALL="/usr/bin/install -c" \
                        INSTALL_DATA="/usr/bin/install -c -m 644" \
                        INSTALL_PROGRAM="/usr/bin/install -c" \
                        INSTALL_SCRIPT="/usr/bin/install -c" \
                        all); then \
          true; \
        else \
          exit 1; \
        fi; \
      else true; \
      fi; \
    fi; \
  done; \
fi
gmake[4]: Entering directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/msoft-float/libgcc'
# If this is the top-level multilib, build all the other
# multilibs.
CONFIG_FILES= CONFIG_HEADERS=auto-target.h:../../../../gcc-9.3.0/libgcc/config.in /bin/sh ./config.status
config.status: creating auto-target.h
config.status: auto-target.h is unchanged
config.status: executing default commands
# Early copyback; see "all" above for the rationale.  The
# early copy is necessary so that the gcc -B options find
# the right startup files when linking shared libgcc.
/bin/sh ../../../../gcc-9.3.0/libgcc/../mkinstalldirs ../../.././gcc/msoft-float
parts="";                                       \
for file in $parts; do                                  \
  rm -f ../../.././gcc/msoft-float/$file;               \
  /usr/bin/install -c -m 644 $file ../../.././gcc/msoft-float/; \
  case $file in                                         \
    *.a)                                                \
      /home/ataylor/cross-compiler/pdp11-gcc9.3.0/pdp11-aout/bin/ranlib ../../.././gcc/msoft-float/$file ;;     \
  esac;                                                 \
done
dest=../../.././gcc/include/tmp$$-unwind.h; \
cp unwind.h $dest; \
chmod a+r $dest; \
sh ../../../../gcc-9.3.0/libgcc/../move-if-change $dest ../../.././gcc/include/unwind.h
#: not found
gmake[4]: *** [Makefile:1109: install-unwind_h-forbuild] Error 127
gmake[4]: Leaving directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/msoft-float/libgcc'
gmake[3]: *** [Makefile:1210: multi-do] Error 1
gmake[3]: Leaving directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/libgcc'
gmake[2]: *** [Makefile:127: all-multi] Error 2
gmake[2]: Leaving directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc/pdp11-aout/libgcc'
gmake[1]: *** [Makefile:12488: all-target-libgcc] Error 2
gmake[1]: Leaving directory '/usr/home/ataylor/cross-compiler/pdp11-gcc9.3.0/workdir-gcc'
gmake: *** [Makefile:941: all] Error 2