ppl0: accommodate building for sparc64
gcc: remove some helper vars

These have been moved to buildpkg.
gcc: major update to support sparc64

- Remove $m64run, instead define $multilib
- Set arch helper vars and multilib options based on $build_arch
- Change cpu settings to be based on build_arch instead of vendor
- Add cpu settings for sparc64 targets
- Add configure options for sparc64 target
- Refactor redo_libs into a generic helper and a wrapper that
  automatically handles multilib builds
gcc: add helper for redoing hardlinks

This consolidates the hardlink->symlink handling in each gcc build script.
gcc*: update build.sh to the new way of handling multilib builds
gcc*: use redo_bin helper for hardlink->symlink conversion
gcc*: remove leftover $iprefix
gcc45: accommodate building for sparc64
gcc48: accommodate building for sparc64
gcc47: accommodate building for sparc64
gcc*: remove configure logging (done by buildpkg now)
isl011: accommodate building for sparc64
cloog018: accommodate building for sparc64
cloog015: accommodate building for sparc64
mpc: add missing license text