added pure python memory profiling package
Prepend PKG_CONFIG_PATH in when_build_dependency.

This helps avoiding accidents where we accidentally use
a system package despite specifying a local package.
Add Piranha package
Work around libiconv failing where there is a more modern version of glibc

libiconv fails to build on ubuntu 14.04 and errors with this without the patch

    In file included from progname.c:26:0:
    ./stdio.h:1010:1: error: 'gets' undeclared here (not in a function)
    _GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
     ^
Add PATH to environment when libiconv is a build dependency
Add PATH to environment when gettext is a build dependency
Merge pull request #318 from jcftang/wip-libiconv-ubuntu1404_glibc_workaround

Work around libiconv failing where there is a more modern version of gli...
Merge pull request #319 from jcftang/wip-update-git

Depend on gettext as well
Add $ARTIFACT/bin to PATH when build dependency
Merge pull request #320 from jcftang/wip-add-to-path-when-build-dep

Add $ARTIFACT/bin to PATH when build dependency
Initial add of flex, it's needed to build libnl3
Depend on m4, bison needs m4 to build
Merge pull request #322 from jcftang/wip-add-flex

Initial add of flex, it's needed to build libnl3
Update Arb to 2.1.0

I am using the git commit taken from the 2.1.0 tag:

https://github.com/fredrik-johansson/arb/releases/tag/2.1.0
Update Flint to 2.4.4

This uses the official tarball. Previously we had to use Fredrik's personal
copy, as that was the only one compatible with Arb. Now the official Flint is
compatible as well, so we should use it from now on.
Merge pull request #324 from hashdist/arb

Update Arb and Flint
Apply patch to libiconv only on linux where modern versions of glibc causes build issues
Revert "Sphinx should be a distutils package"

Fixes #327.

This reverts commit 9bf384a00c14976498745939d4065d9b291b871d.
Merge pull request #326 from jcftang/wip-apply-libiconv-only-on-linux

Apply patch to libiconv only on linux where modern versions of glibc cau...
Tweak openssl package to deal with not being 64bit on OSX