Have a bash function to build each dependency with the same commands. There is
a tradeoff: having each dependency build with the same function means you can't
easily tweak one of the dependencies. OTOH having a unified function means a)
more readable script, b) that we're sure not to forget some steps and c) no
need to do the same edit n times.
Set the PKG_CONFIG_PATH globally. Also a tradeoff: if a future addition
wouldn't need the same PKG_CONFIG_PATH, this would make things ugly. But that
is actually quite unlikely, and the readability improvement is substantial.
Use env variables to remember local paths. That means we always are sure to cd
to the same absolute base path, which a 'cd ..' can't guarantee; also, we avoid
possible typos for e.g. "$deps/install".
Change-Id: Ib23f86c6cc1441d882de59bcdde5de87fa4e9fdf
Neels Hofmeyr