In one of the latest patches I introduced a bug which caused
the --builddir option of dunecontrol to not make any effect.
This patch fixes this.

Previously a value specified on the command line was always
overwritten by a value set in an options file. This patch
fixes this together with overwriting the build directory with
the default build-cmake when --use-cmake was specified.

GNU xargs behaves differently from BSD xargs in that it always executes the command
at least once, even if there are no arguments on stdin.
As noticed by Martin, this behavior breaks the whitespace hook if the list of files to
be checked is empty. In that case, the hook will now check *all* staged changes, resulting
in false alarms.

So we test which version of xargs we have and use the correct flags in either case. If neither
one works, we bail out and ask the user to file a bug, but this behavior can be overriden with
the environment variable DUNE_WHITESPACE_IGNORE_XARGS.

Fixes FS#1316.

CMake honors the familar compiler flags if they are exported. This patch
extracts them from CONFIGURE_FLAGS and exports them to cmake by putting
them in from of the cmake call.

Previously we relied on CMake's export(PACKAGE ...) function when
finding dune packages without dune-control. This is error prone
when using several instances of a dune-module (either with differing
versions or built using different options). In this case there is no
control which of the instances is used.

Now we try to guess the correct build directory, if it was not
provided with ${module}_DIR, ${module}_Root or in the
CMAKE_PREFIX_PATH. Note that when using dunecontrol ${module}_DIR will
always be set. We take the path of the current toplevel build
directory and simply substitute any occurence of the name of current
module with name of the module that we try to find. This works for
both  building in a subdirectory of the source tree
(e.g. ${module-source}/build-cmake) or in a sibling directory
containing the module name (e.g. ${module}-build).

MPI_FOUND is already deprecated in CMake 2.8.6 - our minimal
required version.

The contents of the files containing git settings is evaluated by the shell, which can
be dangerous if such a file contains a line like 'option value; rm -rf /'. While that is
unlikely, it might happen when people try to create a Git alias.

It would be possible to completely protect users from this problem by parsing the line
completely manually (without involving the shell), but on the other hand, being able to
use shell features for determining option values seems like a good thing to have as well.

This patch adds some rudimentary protection that protects against errors like the one shown
above. More advanced users can still wreak havoc by abusing shell substitution
('option $(echo value; rm -rf /)' comes to mind), but that's not something our average user
will do.

The protection works by splitting the input line into an array first; doing so does not
actually execute the line and so prevents anything outside of value substitutions in $()
from being executed.

Also added a comment to explain why we need to go through the extra step with the array.

As Carsten correctly pointed out, it's easier to just eval the command directly.

Make sure to always quote paths that are relative to PREFIX_DIR, as that variable
may contain spaces.

Some Dune users like to aggregate all the Dune modules required for a project by
creating a Git repository with a Git submodule for every submodule. Unfortunately,
dunecontrol currently doesn't recognize the submodule repositories currently because
Git aggregates all repositories in the .git directory of the superproject (more
preciselyin in the subdirectory .git/modules/). In the submodule, .git is a regular
file that contains a referral to the actual repository directory.

This patch fixes the problem by

- Detecting Git directories by looking for both directories and regular files called
  .git in the module directory.

- Following the referral in submodules for the hook setup to make sure the hook gets
  installed in the correct location.

Fixes FS#1303.

dunecontrol fails to properly process Git settings where the value contains
spaces. It was supposed to handle quoting the same way the shell does, but
instead arguments were split at each space and quotes kept verbatim in the
split arguments.

The reason is the order in which the shell performs variable substitution and
tokenizing, preventing the line with the Git configuration entry from being
tokenized by the shell.

This patch fixes the problem by first parsing the line into an array, which is
then in turn expanded again with correct per-element quoting.

In addition, make COMMENT helper variables local while we're at it.

quick-fix to make CMAKE builds respect the DUNE_BUILDDIR entry in opts
files

This patch makes it possible to bypass installation of the whitespace hook by specifying

VCSETUP_FLAGS="DISABLEWHITESPACEHOOK=1"

in the user's options. If dunecontrol encounters that flag, it will not attempt to install
the hook in any module, uninstall the hook if it has already been installed and output a
warning telling the user that he'll have to take care of whitespace by himself.

[[Imported from SVN: r7471]]

This patch allows the user to specify a file with Git configuration options that
will be applied during the vcsetup phase, which might be used to set a custom identity
within the repository (e.g. an @dune-project.org email address) or to set up personal
aliases.

In order to enable this feature, put the line
VCSETUP_FLAGS="GIT_CONFIG_FILE=</path/to/your/config/file>"
into your options file. The configuration file itself is fed to the command
"git config" line-by-line, so you can normally set an option by simply having a
line like "config_key value" in the configuration file. Lines starting with # are
skipped and can be used for comments.

[[Imported from SVN: r7470]]

This patch hooks vcsetup into the standard "dunecontrol all" incantation
that most users are likely invoke after cloning a repository. By running
vcsetup that way, most Dune users will automatically have the whitespace hook
installed, which should greatly improve the usability of user-submitted patches.

[[Imported from SVN: r7468]]

This patch adds the new command "vcsetup" to dunecontrol. This command
is intended to perform various setup actions on a module that has been
checked out from a version control system.

For now, the command

- installs the whitespace hook bin/git-whitespace-hook as a Git pre-commit hook
  if all of the following conditions are met:
  - the current module is a Git repository
  - the dune.module file contains the line "Whitespace-Hook: Yes"
  - there is no existing pre-commit hook that would be overwritten
  The script detects older versions of the whitespace hook and updates them
  if necessary.

- applies Git configuration settings from the file .vcsetup/config.
  The contents of the file is simply fed to "git config" line by line. That
  way, Git configuration keys can be set by simply adding a line of the form
  "key value". Lines starting with "#" are filtered out and can thus be used
  for comments.

- runs all executable files in the directory .vcsetup/run.d
  This can be used for more elaborate setups. Note that these scripts are run
  if any of the following files/directories are found: .git .svn CVS stamp-vc

[[Imported from SVN: r7467]]

bin/git-whitespace-hook is a Git pre-commit hook that enforces our
whitespace policy for local commits. By installing this hook in a
local Git repository, users can make sure that there won't be any
nasty surprises when trying to merge their commits to the central
repository later on.

[[Imported from SVN: r7466]]

[[Imported from SVN: r7455]]

[[Imported from SVN: r7450]]

translating options for provided for configure to CMake syntax.

[[Imported from SVN: r7448]]

[[Imported from SVN: r7447]]

[[Imported from SVN: r7374]]

Revision 7117
.----------------------
Make autotools the default build system. 

One can select CMake using the --use-cmake switch. This prepares
the merge to the trunk.



[[Imported from SVN: r7360]]