* genscripts.sh (LIB_PATH): For native targets, concatenate $libdir
and $NATIVE_LIB_DIRS. Add $tool_lib before other libs.
(LIB_SEARCH_DIRS): No need to use "tr".
(COMPILE_IN): Only set for native targets.
* configure.host (NATIVE_LIB_DIRS): Specify all native search dirs
here, rather than adding lib:/usr/lib:/usr/local/lib in genscripts.sh.
* configure.tgt (powerpc*): Set tdir_*.
(powerpcle*): Correct targ_extra_emuls.
* emulparams/elf32ppc.sh (LIB_PATH): Set up native 64 bit dirs.
* emulparams/elf64ppc.sh (LIB_PATH): Likewise.