paul@jacko:~/gpc1-build$ LANG=C make
make[1]: Entering directory '/home/paul/gpc1-build/libiberty'
make[2]: Entering directory '/home/paul/gpc1-build/libiberty/testsuite'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/paul/gpc1-build/libiberty/testsuite'
make[1]: Leaving directory '/home/paul/gpc1-build/libiberty'
make[1]: Entering directory '/home/paul/gpc1-build/intl'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/paul/gpc1-build/intl'
make[1]: Entering directory '/home/paul/gpc1-build/gcc'
cd ../../gpc1/gcc-3.4.6/gcc/p/rts && make -f Makefile.in srcdir=. GCC_VERSION="3.4.6" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" GPC_DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" generated-files
make[2]: Entering directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[2]: Nothing to be done for 'generated-files'.
make[2]: Leaving directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
cd ../../gpc1/gcc-3.4.6/gcc/p/rts && make -f Makefile.in srcdir=. GCC_VERSION="3.4.6" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" GPC_DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" generated-files
make[2]: Entering directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[2]: Nothing to be done for 'generated-files'.
make[2]: Leaving directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
cd ../../gpc1/gcc-3.4.6/gcc/p/rts && make -f Makefile.in srcdir=. GCC_VERSION="3.4.6" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" GPC_DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" generated-files
make[2]: Entering directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[2]: Nothing to be done for 'generated-files'.
make[2]: Leaving directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
cd ../../gpc1/gcc-3.4.6/gcc/p/rts && make -f Makefile.in srcdir=. GCC_VERSION="3.4.6" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" GPC_DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" generated-files
make[2]: Entering directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[2]: Nothing to be done for 'generated-files'.
make[2]: Leaving directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
cd ../../gpc1/gcc-3.4.6/gcc/p/rts && make -f Makefile.in srcdir=. GCC_VERSION="3.4.6" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" GPC_DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" generated-files
make[2]: Entering directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[2]: Nothing to be done for 'generated-files'.
make[2]: Leaving directory '/home/paul/gpc1/gcc-3.4.6/gcc/p/rts'
make[1]: Circular libgcc.a <- pascal dependency dropped.
make \
  CFLAGS="-g -O2 -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long  " \
  CONFIG_H="tconfig.h ../../gpc1/gcc-3.4.6/gcc/../include/ansidecl.h" TM_H="tm.h      ../../gpc1/gcc-3.4.6/gcc/config/i386/biarch64.h ../../gpc1/gcc-3.4.6/gcc/config/i386/i386.h ../../gpc1/gcc-3.4.6/gcc/config/i386/unix.h ../../gpc1/gcc-3.4.6/gcc/config/i386/att.h ../../gpc1/gcc-3.4.6/gcc/config/dbxelf.h ../../gpc1/gcc-3.4.6/gcc/config/elfos.h ../../gpc1/gcc-3.4.6/gcc/config/svr4.h ../../gpc1/gcc-3.4.6/gcc/config/linux.h ../../gpc1/gcc-3.4.6/gcc/config/i386/x86-64.h ../../gpc1/gcc-3.4.6/gcc/config/i386/linux64.h ../../gpc1/gcc-3.4.6/gcc/defaults.h insn-constants.h insn-flags.h" \
  INCLUDES="-I. -I. -I../../gpc1/gcc-3.4.6/gcc -I../../gpc1/gcc-3.4.6/gcc/. -I../../gpc1/gcc-3.4.6/gcc/../include " \
  MAKEOVERRIDES= \
  -f libgcc.mk all
make[2]: Entering directory '/home/paul/gpc1-build/gcc'
for d in libgcc 32 libgcc/32; do \
  if [ -d $d ]; then true; else /bin/sh ../../gpc1/gcc-3.4.6/gcc/mkinstalldirs $d; fi; \
done
if [ -f stmp-dirs ]; then true; else touch stmp-dirs; fi
/home/paul/gpc1-build/gcc/xgcc -B/home/paul/gpc1-build/gcc/ -B/usr/local/x86_64-unknown-linux-gnu/bin/ -B/usr/local/x86_64-unknown-linux-gnu/lib/ -isystem /usr/local/x86_64-unknown-linux-gnu/include -isystem /usr/local/x86_64-unknown-linux-gnu/sys-include -O2  -DIN_GCC    -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -fPIC -g -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED  -I. -I. -I../../gpc1/gcc-3.4.6/gcc -I../../gpc1/gcc-3.4.6/gcc/. -I../../gpc1/gcc-3.4.6/gcc/../include  -fexceptions -c ../../gpc1/gcc-3.4.6/gcc/unwind-dw2.c -o libgcc/./unwind-dw2.o
../../gpc1/gcc-3.4.6/gcc/unwind-dw2.c: In function `uw_frame_state_for':
../../gpc1/gcc-3.4.6/gcc/unwind-dw2.c:1031: error: dereferencing pointer to incomplete type
make[2]: *** [libgcc.mk:236: libgcc/./unwind-dw2.o] Error 1
make[2]: Leaving directory '/home/paul/gpc1-build/gcc'
make[1]: *** [Makefile:1228: libgcc.a] Error 2
make[1]: Leaving directory '/home/paul/gpc1-build/gcc'
make: *** [Makefile:23375: all-gcc] Error 2
paul@jacko:~/gpc1-build$

"The “dereferencing pointer to incomplete type” error commonly occurs in C when one tries to dereference a type (usually a struct) that is:

The error in the first bullet point occurs because C cannot find the struct that is being dereferenced. The reason for this could be that the struct may not have been declared, or that the user made a typographical error in the struct’s name"

from: https://www.educative.io/edpresso/resolving-the-dereferencing-pointer-to-incomplete-type-error

At this stage, it seems to use generated xgcc to compile itself... a bit weird it get errors at this stage to me.

Will investigate a bit more later.