The FTP server what we get libpng from only keeps the latest version in its main folder. Older versions are in the "history" folder. Apparently version 1.6.9 has been released, so 1.6.8 has moved to the history folder.
Instead of using the boost provided by Ubuntu 12.04, build our own
dependency like we do for Windows.
This allows using a much newer version (1.55 versus 1.46) as well as
building with `-fPIC` so that `-pie` can be used in the x86-64 build.
0425715 gitian: add explicit dependency build for linux (Wladimir J. van der Laan)
279af1a build: use Ubuntu 12.04 for linux gitian build (Wladimir J. van der Laan)
This commit adds a step, which is to git checkout the version to be
built. This ensures that the gitian-descriptors for said version will be
the correct ones. In addition, it updates the links for several
dependencies, where the previously existing links were dead.
Workaround 1.54.0 build bug, upstream #9156
Workaround 1.51.0+ human bug, upstream #7262
This commit also demonstrates a method to verify the integrity of inputs.
