> Basically, you need to FIRST build a new compiler and install it, THEN a 
	> make build.
	Which I cannot do, as this is sparc64. Apparently the mainline toolchain
	is not considered useful there (at least gnu/usr.bin/egcs/Makefile won't
	build any compiler components on sparc64). 

I presume you haven't read the faq http://www.netbsd.org/Ports/sparc64/faq.html#compile-cc:

  How do I build the new compiler? (top)                                                                          
                                                                                                                  
           As of 20000927, the sparc64 port uses it's own gcc 2.95. Here's how to build and install it (in        
           /usr/local!):                                                                                          
              * cd src/gnu/dist/toolchain                                                                         
              * mkdir builddir                                                                                    
              * contrib/egcs_update --touch                                                                       
              * cd builddir                                                                                       
              * ../configure                                                                                      
              * make (you can set LANGUAGES=c if you don't want the others)                                       
              * make install                                                                                      
              * rm -fr /usr/local/lib/gcc-lib/*/2.95.2/include                                                    
           If your build breaks with "Fatal error: Can't extend frag 90. chars", you can try removing "-g" from   
           CFLAGS in src/gnu/dist/toolchain/builddir/binutils/Makefile.                                           
                                                                                                                  

Eduardo