samples: add arm-cortexa5-linux-uclibcgnueabihf

This configuration has been tested on an Atmel sama5d3 board. It is a Cortex-A5
without neon and the floating point unit is a vfpv4-d16.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Add main EXPERIMENTAL_PATCHES setting

This change adds support for experimental patches to be introduced to
crosstool-ng. The patches enabled by this option are to be located here:

    patches/experimental/<package>/<version>/XXXX-NAME.patch

Where, XXXX is the patch number to be applied in order, like:
    0001-some_patch_one.patch
    0002-some_patch_two.patch
    9999-some_patch_to_be_applied_last.patch

In the first patch series, all patches in the EXPERIMENTAL_PATCHES
option will be applied all at once, or none at all.

In a later [RFC] patch, I plan on adding finer tuned patch
enable/disable options based on the name of the patch and where it is
located in the patches/experimental sub-tree. So the name of the patch
should use underscores between words in the patch name.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[yann.morin.1998@free.fr: slightly reword prompt]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
libc: rename the threads options

Use a more coherent naming for the options. This will help commonalise
the native case (e.g. NPTL on Linux, win32 on Windows), and add alternate
implementations (e.g. musl.)

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Bryan Hundven <bryanhundven@gmail.com>
libc: libces are responsible for naming their threads implementation

This will help add new implementations, such as the one in musl.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Bryan Hundven <bryanhundven@gmail.com>
libc/mingw: threads are the native ones

There is no need to differentiate the win32 threads case, since we
can cosider them to be the native implementation on Windows.

Besides, with the previous patch, nothing uses it anymore.

So, just remove it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc Bryan Hundven <bryanhundven@gmail.com>
libc/musl: add musl-libc support

This patch adds initial support for musl-libc.

Musl-libc versions currently supported:
* 1.0.3 (Stable)
* 1.1.3 (Previous Mainline)
* 1.1.4 (Mainline)

Futher improvements are needed.
* gcc-4.9.x has issues (Might be fixed in musl-1.1.4).
* Multilib support is needed.
* Checks to make sure paths are correct.
* Move to 2-step gcc build. 3-step build is not necessary.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[yann.morin.1998@free.fr: removed the gcc musl patch, to be added later;
 removed dead code do_get_arch()]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
patches