Problems building GNAT on OS X with top-of-tree

[Geert Bosch <bosch@gnat.com>]

I am trying to get up to speed with the head of the GCC tree, but while
building stage2 of the GNAT, any non-trivial file fails to compile with
assembler errors as follows:

stage1/xgcc -Bstage1/ -B/usr/local/powerpc-apple-darwin6.1/bin/ -c -g 
-O2      -gnatpg -gnata -g -O1 -fno-inline \
  -I- -I. -Iada -I/Users/bosch/gcc/gcc/ada 
/Users/bosch/gcc/gcc/ada/a-except.adb -o ada/a-except.o
a-except.s:unknown:Can't emit reloc {- symbol "L65$pb"} @ file address 
9408.
a-except.s:unknown:Can't emit reloc {- symbol "L65$pb"} @ file address 
9404.
a-except.s:unknown:Can't emit reloc {- symbol "L64$pb"} @ file address 
9296.
a-except.s:unknown:Can't emit reloc {- symbol "L64$pb"} @ file address 
9292.
a-except.s:unknown:Can't emit reloc {- symbol "L64$pb"} @ file address 
9216.
a-except.s:unknown:Can't emit reloc {- symbol "L64$pb"} @ file address 
9212.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
9056.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
9052.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8868.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8864.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8680.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8676.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8572.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8568.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8532.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8528.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8452.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8448.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8360.
a-except.s:unknown:Can't emit reloc {- symbol "L63$pb"} @ file address 
8356.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
6140.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
6136.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5980.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5976.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5952.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5948.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5824.
a-except.s:unknown:Can't emit reloc {- symbol "L43$pb"} @ file address 
5820.
a-except.s:unknown:Can't emit reloc {- symbol "L42$pb"} @ file address 
5468.
a-except.s:unknown:Can't emit reloc {- symbol "L42$pb"} @ file address 
5464.

I guess this refers to code like:
         addis r9,r31,ha16(
L_system__soft_links__get_jmpbuf_address$non_lazy_ptr-
L42$pb)
         lwz 
r9,lo16(L_system__soft_links__get_jmpbuf_address$non_lazy_ptr-
L42$pb)(r9)

Indeed, this looks dubious and IIRC, there was a similar problem a long
while ago. Do these symptoms ring a bell with anyone? If not, I'll see
if I can debug this and see why this code gets generated. Thanks in
advance for any help.

   -Geert