Excerpts from mail: 28-Feb-101 Re: building current by eeh@netbsd.org 
> You need to install a patch to 1.5 to fix /usr/bin/cpp
> or make sure you install the correct shell script to fix
> this.
Running make build causes a make install to run in
/usr/src/gnu/usr.bin/egcs fairly early in the process.
New compilers are not built, but /usr/bin/cpp and some info files are
replaced. This process will presumably overwrite any patch I install...
  
> Obviously your `envp' has gotten corrupted and lost the
> high bits.  This is probably due to a mis-match between
> the kernel and crt0.  Make sure your kernel is newer
> than your crt0.o.
Kernel is not newer that crt0. I seem to have mis-interpreted the "Old
compatibility hack removed." thread (which caused me to believe that the
userland upgrade needed to happen first, despite the fact that you
clearly stated that the kernel upgrade should be done first in your
initial message.). I'll try rebuilding the kernel once I find the cpp
patch (assuming that rebuilding csu with a proper cpp is insufficient).

(FWIW, the problem occurs with both static and dynamic binaries.)