cibuild depends on xctool.
bootstrap does not depend on xctool.
Makefile: add prefix_install target.

Add a Makefile target to do a more normal Unix-style prefix install.
Merge pull request #205 from mikemcquaid/make-install

Makefile: add prefix_install target.
Correct the indentation.
Merge pull request #197 from Carthage/homebrewable

Homebrewable
Merge branch 'master' into 0.4-development