csage: initial autotools version
c_lib: derp, continuing ignoring so's
Merge remote-tracking branch 'origin/develop' into ticket/15594
Merge commit '144d006f9185299c4121eb94bd606ee1fb16d992' into HEAD

Conflicts:
	src/c_lib/SConstruct
Further develop c_lib autotools project
bootstrap: use glibtoolize by default on OS X

Since OS X's libtool is a completely different
beast from GNU's libtool, it is common convention
to prefix the GNU versions with g on the platform.
Trac #15594: Use autotools for csage

Use autotools instead of scons to build `c_lib`. After this change,
polybori is the only part of Sage using scons.

URL: http://trac.sagemath.org/15594
Reported by: ohanar
Ticket author(s): R. Andrew Ohana, Jeroen Demeyer
Reviewer(s): R. Andrew Ohana, Jeroen Demeyer