scripts: add support for building manuals

Add support for building the HTML and PDF manuals for the major
components. Implement for binutils, GCC, GDB, and GLIBC.

Always build all manuals and install a subset. Be explicit about the
subset to reduce the clutter and to avoid getting copies of common
manuals like bfd from all of the sourceware based components. Downside of
being explicit is that you need to update it when a new component
comes along.

Build the manuals as part of the last GCC build, namely 'cc' for glibc
based ones and cc_core_pass_2 for baremetal.

An example of the output is at:
http://people.linaro.org/~michaelh/incoming/crosstool-NG/

Signed-off-by: Michael Hope <michael.hope@linaro.org>
[yann.morin.1998@anciens.enib.fr: depends on ! remove docs; gold manual install]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

docs: Add strategies for assembling root filesystems.

Expand the documentation for using a crosstool-NG-generated toolchain for
building a root filesystem for a target device.

Signed-off-by: "Trevor Woerner" <twoerner@gmail.com>
yann.morin.1998@anciens.enib.fr: some eye-candy]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

scripts: use wget, not curl

It seems wget is more popular than curl.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

scripts: use the floating-point string option in tests

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

libc/uClibc: use the floating-point string option in tests

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

arch/sh: use the floating-point string option in tests

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

arch/x86: prescott is an i686

let CT_ARCH_ARCH=prescott result in a i686 tuple prefix

Signed-off-by: Titus von Boxberg <titus@v9g.de>