I've been daring again and tried to build a -current tree (of a few days
ago) on my amd64. Unfortunately an internal gcc problem is triggered.
Here is the relevant output:

===> build.sh command: ./build.sh -D /vol1/rhialto/destdir.vax -m vax -O /scratc
h2/obj.vax -R /vol1/rhialto/release -T /vol1/rhialto/tools.amd64 -u -U -N 1 -X /
vol1/rhialto/cvs/xsrc -x release
===> build.sh started: Sat Jul  7 00:06:23 CEST 2007
===> NetBSD version:   4.99.22
===> MACHINE:          vax
===> MACHINE_ARCH:     vax
===> Build platform:   NetBSD 3.0 amd64
===> HOST_SH:          /bin/sh
===> TOOLDIR path:     /vol1/rhialto/tools.amd64
===> DESTDIR path:     /vol1/rhialto/destdir.vax
===> RELEASEDIR path:  /vol1/rhialto/release
===> makewrapper:      /vol1/rhialto/tools.amd64/bin/nbmake-vax
===> Updated /vol1/rhialto/tools.amd64/bin/nbmake-vax

...

dependall ===> x11/bin/lbxproxy
    compile  lbxproxy/atomcache.o
    compile  lbxproxy/cache.o
    compile  lbxproxy/cmap.o
    compile  lbxproxy/cmaputil.o
    compile  lbxproxy/dispatch.o
    compile  lbxproxy/extensions.o
    compile  lbxproxy/gfx.o
    compile  lbxproxy/globals.o
    compile  lbxproxy/init.o
    compile  lbxproxy/lbxfuncs.o
    compile  lbxproxy/lbxutil.o
    compile  lbxproxy/main.o
    compile  lbxproxy/options.o
    compile  lbxproxy/pm.o
    compile  lbxproxy/props.o
    compile  lbxproxy/reqtype.o
    compile  lbxproxy/resource.o
    compile  lbxproxy/swaprep.o
    compile  lbxproxy/swapreq.o
    compile  lbxproxy/tables.o
    compile  lbxproxy/tags.o
    compile  lbxproxy/unsquish.o
    compile  lbxproxy/utils.o
    compile  lbxproxy/wire.o
    compile  lbxproxy/WaitFor.o
    compile  lbxproxy/connection.o
/vol1/rhialto/cvs/xsrc/xfree/xc/programs/lbxproxy/os/connection.c: In function 'OnlyListenToOneClient':
/vol1/rhialto/cvs/xsrc/xfree/xc/programs/lbxproxy/os/connection.c:808: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.NetBSD.org/Misc/send-pr.html> for instructions.

*** Failed target:  connection.o
*** Failed command: /vol1/rhialto/tools.amd64/bin/vax--netbsdelf-gcc -O1 -fgcse -fstrength-reduce -fgcse-after-reload -fno-strict-aliasing -Werror -I/vol1/rhialto/destdir.vax/usr/X11R6/include/X11 -I/vol1/rhialto/destdir.vax/usr/X11R6/include/X11/extensions -I/vol1/rhialto/cvs/xsrc/xfree/xc/programs/lbxproxy/include -DSHAPE -DXKB -DLBX -DXAPPGROUP -DXCSECURITY -DTOGCUP -DXF86BIGFONT -DDPMSExtension -DPIXPRIV -DPANORAMIX -DRENDER -DRANDR -DGCCUSESGAS -DAVOID_GLYPHBLT -DSINGLEDEPTH -DXvExtension -DXFree86Server -DXvMCExtension -DSMART_SCHEDULE -DBUILDDEBUG -DXResExtension -DNDEBUG -DCSRG_BASED -DFUNCPROTO=15 -DNARROWPROTO -I/vol1/rhialto/destdir.vax/usr/X11R6/include -nostdinc -isystem /vol1/rhialto/destdir.vax/usr/include -c -O2 -DTCPCONN -DUNIXCONN -DHAS_STICKY_DIR_BIT -DHAS_FCHOWN -DIPv6 -DDDXOSINIT -DSERVER_LOCK -DDDXOSFATALERROR -DDDXOSVERRORF -DDDXTIME -DUSB_HID -DLBXPROXY_t -DTRANS_SERVER -DBSD44SOCKETS /vol1/rhialto/cvs/xsrc/xfree/xc/programs/lbxproxy/os/connection.c
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11/bin/lbxproxy

*** Failed target:  dependall
*** Failed command: cd /vol1/rhialto/cvs/src/x11/bin/lbxproxy; /vol1/rhialto/tools.amd64/bin/nbmake realall
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11/bin/lbxproxy

*** Failed target:  dependall-lbxproxy
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this="x11/bin/"; real="/vol1/rhialto/cvs/src/x11/bin" ;; *) this="x11/bin/${dir}/"; real="/vol1/rhialto/cvs/src/x11/bin/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget lbxproxy dependall
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11/bin

*** Failed target:  dependall-bin
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this="x11/"; real="/vol1/rhialto/cvs/src/x11" ;; *) this="x11/${dir}/"; real="/vol1/rhialto/cvs/src/x11/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget bin dependall
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11

*** Failed target:  do-build
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this="x11/"; real="/vol1/rhialto/cvs/src/x11" ;; *) this="x11/${dir}/"; real="/vol1/rhialto/cvs/src/x11/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget . dependall
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11

*** Failed target:  build
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this="x11/"; real="/vol1/rhialto/cvs/src/x11" ;; *) this="x11/${dir}/"; real="/vol1/rhialto/cvs/src/x11/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget . do-build
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src/x11

*** Failed target:  do-x11
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this=""; real="/vol1/rhialto/cvs/src" ;; *) this="${dir}/"; real="/vol1/rhialto/cvs/src/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget x11 build
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src

*** Failed target:  build
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this=""; real="/vol1/rhialto/cvs/src" ;; *) this="${dir}/"; real="/vol1/rhialto/cvs/src/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget . do-x11
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src

*** Failed target:  distribution
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this=""; real="/vol1/rhialto/cvs/src" ;; *) this="${dir}/"; real="/vol1/rhialto/cvs/src/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget . build NOPOSTINSTALL=1
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src

*** Failed target:  release
*** Failed command: _makedirtarget() { dir="$1"; shift; target="$1"; shift; case "${dir}" in /*) this="${dir}/"; real="${dir}" ;; .) this=""; real="/vol1/rhialto/cvs/src" ;; *) this="${dir}/"; real="/vol1/rhialto/cvs/src/${dir}" ;; esac; show=${this:-.}; echo "${target} ===> ${show%/}${1:+ (with: $@)}"; cd "${real}" && /vol1/rhialto/tools.amd64/bin/nbmake _THISDIR_="${this}" "$@" ${target}; }; _makedirtarget . distribution
*** Error code 1

Stop.
nbmake: stopped in /vol1/rhialto/cvs/src

ERROR: Failed to make release
*** BUILD ABORTED ***

Hopefully this means something to somebody.

-Olaf.
-- 
___ Olaf 'Rhialto' Seibert      -- You author it, and I'll reader it.
\X/ rhialto/at/xs4all.nl        -- Cetero censeo "authored" delendum esse.