Add a unit test for the TEST_INCLUDE_DIR and (new) TEST_INCLUDE_DIRS
directory properties.

Add new directory property TEST_INCLUDE_FILES. This supersedes
TEST_INCLUDE_FILE, though the latter is of course retained for
compatibility.

Basically, this is a list rather than a single file. This allows the
feature to be used by generic utilities without conflicting with local
use.

c67bb5ba Clang: Do not add '-std=' options when simulating MSVC
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !982

c96f43b7 include_guard: add tests for the feature
80f1221f include_guard: add doc pages and a release note
85b52a04 include_guard: add vim syntax highlighting rules
d44bd1c2 include_guard: implement new command
Acked-by: Kitware Robot <kwrobot@kitware.com>
Reviewed-by: Craig Scott <craig.scott@crascit.com>
Merge-request: !928

58017517 Ninja: Fix generated command lines for cmake_symlink_* on Windows
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1003

e7936751 curl: Fix build on Haiku
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1006

On Haiku the network functions are in libnetwork, so use it when it
exists.

63fc3bff Check*Source{Compiles,Runs}: Rewrite docs for these modules
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1005

adbd1468 Help: Document the CMAKE_MSVCIDE_RUN_PATH variable.
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1011

The `cl.exe` style command line does not accept the `-std=` options.
Instead behave like MSVC where we don't define standard levels.

Fixes: #16266

d194bd91 FindDoxygen: Add private prefix to internal variables
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1012

Since commit v3.9.0-rc1~55^2 (Improve Doxygen support, 2017-04-10) we
accidentally leave a non-prefixed internal `result` variable set.
This may interfere with project code.  Add a prefix to avoid this.

ec409a11 Vs: fix CSharp custom command by introducing inline MSBuild <Targets>s
dcdab5cf Vs: factor out computation of <Link> tag for CSharp source files
0a8f469a Vs: refactor WriteCustomRule for preparation of CSharp support
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !970

a3e442bb FindCUDA: Fix CUDA_NVCC_FLAGS_<CONFIG> for separable compilation
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1008

46d25e78 FindCUDA: Use find_program if find_host_program is not available
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1009

e03a1b3b target_compile_features: Do not crash on non-enabled language
86990427 Tests: Enable languages explicitly in RunCMake.target_compile_features
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1010

bbc1f364 VS: Fix support for nvcc flags not in our flag table
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1007

The change in commit v3.9.0-rc4~3^2 (VS: Improve workaround for CUDA
-Xcompiler placement bug, 2017-06-21) accidentally appended to the
`AdditionalOptions` as if it were a `;`-separated list, but it is
actually a command-line string.  Append with a space instead.

While at it, fix the same problem for the `AdditionalOptions` added to
`CudaLink` by commit v3.9.0-rc3~1^2 (CUDA: When linking device code
suppress CUDA 8.0+ deprecation warnings, 2017-06-09).

Fixes: #17008

Since commit v3.0.0-rc6~3^2 (FindCUDA: Use CUDA_NVCC_FLAGS* for
separable compilation, 2014-05-18), using the feature for one
configuration results in empty-string ("") arguments on the command line
for other configurations.  This is because the generator expression for
a non-matching configuration evaluates to an empty string but does not
remove the argument.  Use `COMMAND_EXPAND_LISTS` to remove the empty
arguments from the custom command after genex evaluation.

Fixes: #16411

Fixes: #17011

Enable C or CXX (or nothing) as needed in each test case.
This will allow us to add test cases that do not enable CXX.

CMake does not define the `find_host_program` command we've been using
in the cross-compiling code path.  It was provided by a widely used
Android toolchain file.  For compatibility, continue to use
`find_host_program` if available, but otherwise use just `find_program`.

Fixes: #16509

54d42ce7 Vs: disable unnecessary <ItemDefinitionGroups> for CSharp targets
d5f7bf9b Vs: change comparison to use .ProjectType member always as first comparator
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !988

04b2fc08 GCC,Clang: Mark CMAKE_<LANG>_COMPILER_{AR,RANLIB} as advanced
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1001

23451a66 GetPrerequisites: Do not warn about non-absolute UCRT system libraries
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !999

Issue: #17007