package: support multiple patches

With this commit, we extend the behaviour of the <pkg>_PATCH variable
so that it now allows to list several patches to be downloaded and
applied, and no longer just one patch.

This will be useful for the elfutils package, and should anyway not
break the existing behaviour for packages using just one patch.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
docs/manual: update to mention the multiple patches support

After the modification of the <pkg>_PATCH semantic, let's update the
documentation accordingly.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: new package

This patch adds a a package for elfutils. For now, the package is
glibc specific, as adding uClibc support for this package is quite
tedious, and will therefore be done through followup patches.

Heavily based from work done by Stefan Fröberg, but with many further
modifications by Thomas Petazzoni.

Signed-off-by: Stefan Fröberg <stefan.froberg@petroprogram.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: make it possible to only install the libraries

Add and use a --{enable,disable}-progs configuration option to
selectively enable or disable the elfutils programs. Generally, on an
embedded system, the libraries are more useful than the programs, and
being able to not build the programs will make it easier to build the
elfutils libraries on uClibc.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
perf: new package

This patch adds a new package that allows to build the 'perf'
userspace tool that comes in the tools/perf directory of the kernel
sources.

It is an alternative proposal to the one done by Kaiwan Billimoria
<kaiwan.billimoria@gmail.com>, in that it creates the package in
package/perf/. It therefore properly integrates with the Buildroot
package infrastructure.

Of course, the package depends on the Linux kernel to be built by
Buildroot, in order to get Perf sources matching the version of the
kernel that will be executed.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
perf: allow build against libelf when available

Now that libelf is available thanks to elfutils (for glibc only),
allow to build perf against it if available.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
perf: add kernel version checks

perf is only available since kernel 2.6.31, so if we can't find
tools/perf/Makefile, error out and tell the user about this.

perf without libelf can only be built since kernel 3.7, so error out
and tell the user about this if he's trying to build perf from a < 3.7
kernel without libelf.

Unfortunately, those tests can only be build-time checks as we either
need to know the real kernel version (i.e, using LINUX_VERSION would
not be correct as it can be a Git commit ID, or Git tag), or have
access to the kernel sources themselves. So we can't prevent those
invalid situations at the configuration, we can only nicely tell the
user at build time.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
argp-standlone: build position independent code

Even though argp-standalone is built as a static library, it might get
linked in a shared library, so we must built it as
position-independent code.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: argp-standalone usage

elfutils uses the argp family of functions, that isn't available in
uClibc. So, we add a dependency on argp-standalone if building with
uClibc, and modify elfutils source code to link against argp if
needed.

Heavily based from work done by Stefan Fröberg, but with many further
modifications by Thomas Petazzoni.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: solve memcpy problem

elfutils uses some strange internal alias of memcpy in glibc, so
workaround this when building with uClibc.

Heavily based from work done by Stefan Fröberg, but with many further
modifications by Thomas Petazzoni.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: requires largefile

elfutils unconditionally uses off64_t for example, so largefile is
needed.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: gettext

elfutils is annoying: it needs gettext even if locale support is
disabled...

Heavily based from work done by Stefan Fröberg, but with many further
modifications by Thomas Petazzoni.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: FTS functions

The fts_*() functions are optional in uClibc, and not compiled in our
default configuration. The best option would be to migrate this
elfutils code to the nftw family of functions, but it requires quite
some work.

So we have several options here:

 *) Enable fts_*() functions in our default uClibc configuration. Not
    nice since only one package needs them (the help text of uClibc
    for fts_*() functions explicitly mention that they have been added
    to be able to build elfutils).

 *) Use gnulib, but it is quite heavy to setup, requires modifications
    to configure.ac, and other things.

 *) Copy the fts function from uClibc into elfutils source code. This
    is the solution used below. uClibc is LGPL, and elfutils is
    LGPL/GPL, so there should not be any licensing issue.

Of course, the fts_*() functions are only built if they are not
already provided by the C library.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: towards uClibc support: disable po build

Building the po/ directory complains that the scripts in there have
been generated with gettext 0.17, while we use gettext 0.18 in
Buildroot. Since we don't care that much about po files anyway, just
disable the build of this directory.

Heavily based from work done by Stefan Fröberg, but with many further
modifications by Thomas Petazzoni.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: make available on uClibc toolchains

We finally have all the pieces needed to allow the build of elfutils
on uClibc. Only the libraries can be built, the programs remain
available only for glibc/eglibc toolchains.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
elfutils: needs wchar

elfutils contains a call to wmempcpy, which is only available when the
toolchain has wchar support, so add the dependency.

Also display a comment if the toolchain dependencies are not met.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
linux: fix double LINUX_APPEND_DTB

Introduced by 5b33e0b6a (linux: handle new dtb location since 3.8-rc1 for
appended dtbs).

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
package: add green end sftp server

For sftp support in Dropbear or as an alternative for the built in
sftp support in openssh (or to use standalone).

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
linux: fix appended dtb handling of pre/post v3.8-rc1

The $(wildcard ) doesn't work for LINUX_APPEND_DTB, because the .dtb
doesn't exist yet at that point.

Also factor the common part out.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
x11r7: move X.org server style option

The selection between "modular" server and "Kdrive" server really
belongs as a sub-option of the X.org server itself, rather than as a
global x11r7 option. So we move it under the X.org server option.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>