Trac #15736: libgd: disable fontconfig on OSX

Neither OSX nor Sage ship with fontconfig, but it is sometimes picked up
from third-party distributions (leading to compile failures). Disable on
OSX by default.

Note that upstream changed from "gd" to "libgd", we should probably
update (but on another ticket).

URL: http://trac.sagemath.org/15736
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): Sami Losoi
Trac #15682: tachyon (Sage 6.0) does not build on Raspberry Pi (armv6l)

This was already mentioned in http://trac.sagemath.org/ticket/10820
(comments 10 and 11), but no ticket was opened.
Note: The problem was also mentioned by jpflori in
http://trac.sagemath.org/wiki/ExoticPorts.

A fix is to copy the 3 lines for armv7l in spkg-install (lines 84 to 86)
and c/7/6/.
Since I am new to Trac and git it may take me some time to create the
fix :-/

URL: http://trac.sagemath.org/15682
Reported by: wluebbe
Ticket author(s): Wilfried Luebbe
Reviewer(s): Jean-Pierre Flori
Trac #15694: Remove deprecation warning for elliptic curve isogeny class method

In #12768 a deprecation warning was introduced for the elliptic curve
(over QQ) isogeny_class function together with the parameter
{{{use_tuple}}} which defaults to True (old-style output), though using
this value shows a deprecation warning.

We should switch the default to {{{use_tuple=False}}} and adjust the
doctests accordingly.

I see no particular reason to remove the old-style (and current default)
behaviour altogether, but in any case that would be for another ticket.

URL: http://trac.sagemath.org/15694
Reported by: cremona
Ticket author(s): John Cremona
Reviewer(s): Chris Wuthrich
Trac #15743: Document cancel_alarm() in alarm()

URL: http://trac.sagemath.org/15743
Reported by: jdemeyer
Ticket author(s): Jeroen Demeyer
Reviewer(s): Marc Mezzarobba
Trac #15749: sage -t --new doesn't work when not in SAGE_ROOT

{{{
$ sage -t --new
Running doctests with ID 2014-01-27-21-40-52-1930c2ec.
Doctesting files changed since last git commit
Doctesting 1 file.
sage -t src/sage/doctest/control.py
    IOError in doctesting framework
**********************************************************************
Traceback (most recent call last):
  File "/Users/roed/sage/sage-6.0/local/lib/python2.7/site-
packages/sage/doctest/forker.py", line 2086, in __call__
    doctests, extras = self.source.create_doctests(sage_namespace)
  File "/Users/roed/sage/sage-6.0/local/lib/python2.7/site-
packages/sage/doctest/sources.py", line 627, in create_doctests
    raise IOError(errno.ENOENT, "File does not exist", self.path)
IOError: [Errno 2] File does not exist: 'src/sage/doctest/control.py'

----------------------------------------------------------------------
sage -t src/sage/doctest/control.py  # IOError in doctesting framework
----------------------------------------------------------------------
Total time for all tests: 0.2 seconds
    cpu time: 0.0 seconds
    cumulative wall time: 0.0 seconds
}}}

The solution is a simple fix in `src/sage/doctest/control.py`.

URL: http://trac.sagemath.org/15749
Reported by: roed
Ticket author(s): David Roe
Reviewer(s): Jeroen Demeyer, Punarbasu Purkayastha