The special vectorization test run stays in the local configuration, as it is specific to
dune-common.

Merge branch 'ci/clang-7' into 'master'

See merge request [core/dune-common!583]

  [core/dune-common!583]: Nonecore/dune-common/merge_requests/583

Merge branch 'feature/std-negation' into 'master'

ref:core/dune-common This implements c++17's std::negation in namespace
Dune::Std::

See merge request [core/dune-common!582]

  [core/dune-common!582]: gitlab.dune-project.org/core/dune-common/merge_requests/582

This implements c++17's std::negation in namespace Dune::Std::

Merge branch 'fix/test-target' into 'master'

See merge request [core/dune-common!581]

  [core/dune-common!581]: Nonecore/dune-common/merge_requests/581

Merge branch 'feature/dynamic-static-factorial-binomial' into 'master'

ref:core/dune-common Added some dynamic and static methods for calculating
factorials and binomials. There are several different implementation in
several modules of varying accessibility and age which can be replaced by
this.

See merge request [core/dune-common!471]

  [core/dune-common!471]: gitlab.dune-project.org/core/dune-common/merge_requests/471

[!576] [math] deduce the return value of Power in order to allow unit value types (see dune-grid#79)

Merge branch 'power-auto' into 'master'

ref:core/dune-common When working with unit value types (e.g. meters, seconds,
\...) the return type of Power is not the value type. This MR changes the
return type to auto to enable automatic type deduction.

See merge request [core/dune-common!576]

  [core/dune-common!576]: gitlab.dune-project.org/core/dune-common/merge_requests/576

Merge branch 'bugfix/self-assignment' into 'master'

ref:core/dune-common Indeed, isNaN could be something complicated, although
normally it just should be double.

See also [!573] and [dune-istl!235]

See merge request [core/dune-common!578]

  [!573]: gitlab.dune-project.org/NoneNone/merge_requests/573
  [dune-istl!235]: gitlab.dune-project.org/Nonedune-istl/merge_requests/235
  [core/dune-common!578]: gitlab.dune-project.org/core/dune-common/merge_requests/578

Indeed, isNaN could be something complicated, although normally it just
should be double.

Merge branch 'feature/prioritize-virtualenv-package-over-venv' into 'master'

ref:core/dune-common The venv packages cannot handle the system interpreter
being a virtualenv in itself - though this is not incommon. The commit just
prioritizes virtualenv and spits out warning if a user runs into the above
scenario.

This merge request supersedes [!559] after @smuething dislike for the former.

See merge request [core/dune-common!560]

  [!559]: gitlab.dune-project.org/NoneNone/merge_requests/559
  [core/dune-common!560]: gitlab.dune-project.org/core/dune-common/merge_requests/560

Merge branch 'feature/add-dunecontrol-cmake-command' into 'master'

See merge request [core/dune-common!574]

  [core/dune-common!574]: Nonecore/dune-common/merge_requests/574

Merge branch 'pivoting_switch' into 'master'

ref:core/dune-common As discussed in [!449], the user should be able to
disable pivoting if needed. This merge request is intended as a basis for
discussion and adds a simple static switch to DenseMatrix to disable pivoting.
Depends on [!449] and [!451], the only relevant commits for the switch are the
last two.

See merge request [core/dune-common!452]

  [!449]: gitlab.dune-project.org/NoneNone/merge_requests/449
  [!451]: gitlab.dune-project.org/NoneNone/merge_requests/451
  [core/dune-common!452]: gitlab.dune-project.org/core/dune-common/merge_requests/452

Merge branch 'let-cmake-disable-pkgconfig-search' into 'master'

For whatever reason we still allow to search for a module with pkg-config if
CMake was not successful. This leads to the weired situation that if we pass
-DCMAKE_DISABLE_FIND_PACKAGE_dune-uggrid=ON to cmake and dune-uggrid is
installed in a default sytem path we will end up with a CMakeCache.txt
actually using dune-uggrid.

This patch is the minimal change to stop searching for a DUNE module with
pkg-config if CMake was instructed not to use it.

See merge request [core/dune-common!569]

  [core/dune-common!569]: gitlab.dune-project.org/core/dune-common/merge_requests/569

For whatever reason we still allow to search for a module
with pkg-config if CMake was not successful. This leads to
the weired situation that if we pass
-DCMAKE_DISABLE_FIND_PACKAGE_dune-uggrid=ON to cmake and
dune-uggrid is installed in a default sytem path we will end
up with a CMakeCache.txt actually using dune-uggrid.

This patch is the minimal change to stop searching for a
DUNE module with pkg-config if CMake was instructed not to
use it.

Merge branch 'fix-typos' into 'master'

See merge request [core/dune-common!568]

  [core/dune-common!568]: Nonecore/dune-common/merge_requests/568

Merge branch 'test-output-iterators' into 'master'

See merge request [core/dune-common!567]

  [core/dune-common!567]: Nonecore/dune-common/merge_requests/567

The immediate motivation for this is VariableBlockVector::CreateIterator
from dune-istl.

Merge branch 'issue/missing_nullopt_in_optional' into 'master'

### Summary

Import types std::nullopt_t, std::in_place_t, and std::bad_optional_access and
instances nullopt and in_place of these types into namespace Dune::Std in the
file <dune/common/std/optional> in case of DUNE_HAVE_CXX_OPTIONAL is defined.

### Motivation

If you have a compiler with c++17 std::optional support, the std
implementation is imported into the namespace Dune::Std, but not all Helper
classes are imported as well, i.e. nullopt_t, nullopt, in_place_t, in_place
and bad_optional_access are missing. So, I neither can use e.g. std::nullopt
nor can I use Dune::Std::nullopt, since the first one is defined whenever
DUNE_HAVE_CXX_OPTIONAL is set and the second one if it is not set.

### Discussion

For the future it has to be decided, whether std::in_place*** is implemented
in <dune/common/std/optional> or better in <dune/common/std/utility>, since in
the std library it is defined there and used not just for optional but also
for variant and any.

See merge request [core/dune-common!442]

  [core/dune-common!442]: gitlab.dune-project.org/core/dune-common/merge_requests/442

The venv packages cannot handle the system interpreter being a virtualenv
in itself - though this is not incommon. The commit just prioritizes virtualenv
and spits out warning if a user runs into the above scenario.

Merge branch 'feature/range-with-enums' into 'master'

Fixes the defect of the single argument range(...) that enum values could not
be used without casting. I would like to see this being backported to 2.6.

See merge request [core/dune-common!553]

  [core/dune-common!553]: gitlab.dune-project.org/core/dune-common/merge_requests/553

Merge branch 'simd-io' into 'master'

Apparently, output of Vc vectors does not work with libc++. I suspect it has
to do with some hackery Vc does in relation to the standard output streams.

This introduces syntax like

      std::cout << Dune::Simd::io(simd_vec) << std::endl;
      std::cout << Dune::Simd::vio(simd_vec) << std::endl;

to produce output like

    <1, 2, 3, 4>

The difference between the two versions is that io() will skip the angle
bracket for one-component vectors, while vio() will always print them.

See merge request [core/dune-common!551]

  [core/dune-common!551]: gitlab.dune-project.org/core/dune-common/merge_requests/551

Apparently, output of Vc vectors does not work with libc++.  I suspect it has
to do with some hackery Vc does in relation to the standard output streams.

This introduces syntax like
```c++
  std::cout << Dune::Simd::io(simd_vec) << std::endl;
  std::cout << Dune::Simd::vio(simd_vec) << std::endl;
```
to produce output like
```
<1, 2, 3, 4>
```

The difference between the two versions is that `io()` will skip the angle
bracket for one-component vectors, while `vio()` will always print them.

Merge branch 'debugalign-overload-min-max' into 'master'

A superficial reading of the standard's LessThanComparable requirement may
suggest that we could actually use std::min() and std::max(). But as it turns
out this isn't all that clear, see
<https://cplusplus.github.io/LWG/issue2114>. libc++ chose LessThanComparable
in a way that requires the result of the comparison to be implicitly
convertible to bool, which we cannot guarantee as we do not want the debug
type the automatically decay into its underlying type in all kinds of
contexts. So we go with the alternative route of overloading min() and max().

Adresses: [core/dune-istl#50]

See merge request [core/dune-common!550]

  [core/dune-istl#50]: gitlab.dune-project.org/core/dune-istl/issues/50
  [core/dune-common!550]: gitlab.dune-project.org/core/dune-common/merge_requests/550

A superficial reading of the standard's LessThanComparable requirement may
suggest that we could actually use std::min() and std::max().  But as it turns
out this isn't all that clear, see https://cplusplus.github.io/LWG/issue2114.
libc++ chose LessThanComparable in a way that requires the result of the
comparison to be implicitly convertible to bool, which we cannot guarantee
as we do not want the debug type the automatically decay into its underlying
type in all kinds of contexts.  So we go with the alternative route of
overloading min() and max().

Adresses: core/dune-istl#50

Merge branch 'bugfix/add_to_unique_ptr_to_CmakeLists' into 'master'

Header was missing in CMakeLists.txt and now breaks code due to usage in
dune-grid Needs to be backported to 2.6

See merge request [core/dune-common!547]

  [core/dune-common!547]: gitlab.dune-project.org/core/dune-common/merge_requests/547