I *just* checked out mainline, and it is failing to build like so: (x86 with checking enabled)
libbackend.a(print-rtl.o): In function `print_decl_name': /src/gcc/2006-05-16/gcc/gcc/print-rtl.c:73: multiple definition of `flag_dump_unnumbered' libbackend.a(options.o):(.bss+0x1ac): first defined here libbackend.a(rtlanal.o): In function `rtx_unstable_p': /src/gcc/2006-05-16/gcc/gcc/rtlanal.c:94: multiple definition of `target_flags' libbackend.a(options.o):(.bss+0x28): first defined here libbackend.a(toplev.o): In function `set_src_pwd': /src/gcc/2006-05-16/gcc/gcc/toplev.c:408: multiple definition of `flag_pcc_struct_return' libbackend.a(options.o):(.bss+0x25c): first defined here libbackend.a(toplev.o): In function `set_src_pwd': /src/gcc/2006-05-16/gcc/gcc/toplev.c:411: multiple definition of `flag_var_tracking' libbackend.a(options.o):(.bss+0x350): first defined here collect2: ld returned 1 exit status make[3]: *** [cc1-dummy] Error 1 rm fsf-funding.pod gcov.pod gfdl.pod cpp.pod gpl.pod gcc.pod make[3]: Leaving directory `/build/gcc/2006-05-16/gcc' make[2]: *** [all-stage1-gcc] Error 2 make[2]: Leaving directory `/build/gcc/2006-05-16' make[1]: *** [stage1-bubble] Error 2 make[1]: Leaving directory `/build/gcc/2006-05-16' make: *** [all] Error 2 Andrew