Tool scripts to build a vanilla toolchain.

 On branch master
 Your branch is up-to-date with 'origin/master'.

 Changes to be committed:
	modified:   README.md
	new file:   tools/README.md
	new file:   tools/build-all.sh
	new file:   tools/build-binutils.sh
	new file:   tools/build-gcc.sh
	new file:   tools/build-newlib.sh
	new file:   tools/build-pk.sh
	new file:   tools/build-spike.sh
	new file:   tools/clone-repos.sh
	new file:   tools/common.sh