* config.gcc (powerpc-*-netbsd*): Replace "svr4.h" with
"netbsd.h netbsd-elf.h" in tm_file.  Set tmake_file to
"${tmake_file} rs6000/t-netbsd".
* config/rs6000/netbsd.h: Rewrite.
* config/rs6000/t-netbsd: New file.

From-SVN: r59479