This reverts commit v3.7.0-rc1~275^2 (Ninja: Use full path for all
source files, 2016-08-05).  Unfortunately using absolute paths can
cause incorrect rebuilds due to ninja limitations.  The ninja
manual [1] explains:

> ... using absolute paths, your depfile may result in a mixture of
> relative and absolute paths. Paths used by other build rules need
> to match exactly.

Passing an absolute path to a source file to the compiler while using a
relative path in the ninja build manifest can cause such mixture and
lead to incorrect rebuilds.  Simply revert the change for now.

Note that there was a follow-up to the original change in commit
v3.7.0-rc2~10^2 (Ninja: Fix RC language depfile generation with
cmcldeps, 2016-10-13).  We don't need to revert that because that
change made the relevant code cleverly adapt to whatever variable
we use to reference the source file.

[1] https://ninja-build.org/manual.html#_deps

Fixes: #16675
Issue: #13894

In commit v3.8.0-rc1~87^2~1 (VS: added support for C#, 2017-01-09) we
removed what looked like a no-op streaming operation but in fact it
is responsible for applying indentation.  Restore the line.

Fixes: #16661

We try to choose the Windows SDK version based on the version of Windows
targeted by the build.  However, if using VS 2017 without the Windows
8.1 SDK installed then we must fall back to the Windows 10 SDK even when
targeting an older version of Windows.

Inspired-by: gnaggnoyil <gnaggnoyil@gmail.com>

It does not actually configure the project to install to the given
location.  That must be done by passing the `<INSTALL_DIR>` placeholder
to the external project configuration step.

Wilfried Goesgens authored Feb 21, 2017 and Brad King committed Feb 21, 2017

It is for the install step of the external project and does not
affect installation of the calling project.

If the property is explicitly set to a non-true value we should
not treat it as true.

Old versions of `libsigc++` do not have the version macros inside of its
`sigc++config.h` header. Assume nothing about such headers and report
version "zero".

Fixes: #16654

In commit v3.4.0-rc1~333^2 (Merge branch 'upstream-kwsys' into
update-kwsys, 2015-07-15) we brought in upstream KWSys commit 86a24794
(SystemTools: Fix GetActualCaseForPath drive letter case handling,
2015-07-09).  This caused our path processing to convert drive letters
to upper-case and exposed an existing bug in our implementation of
CMP0017.

Policy CMP0017 is responsible for ensuring that modules included from a
builtin module only load other builtin modules and cannot be overridden
by a file in `CMAKE_MODULE_PATH`.  If there is a case difference in the
drive letter (or other path components) then the path to the including
module may not match our builtin module directory in a simple string
comparison.  This means builtin modules may not be recognized as such,
and they may not reliably include their builtin dependencies.  For
example, if a project provides a `Platform/Windows` module in
`CMAKE_MODULE_PATH` it can break inclusion of our builtin
`Platform/Windows` module, leading to strange behavior.

Fix this by comparing the path to the including module to our builtin
module directory using a function that is aware of case-insensitivity of
paths on Windows.

Fixes: #16648, #16622

Refactoring in commit v3.6.0-rc1~85^2 (HDF5: Refactor the use of
compiler wrappers, 2016-04-04) converted code of the form

    if(${LANGUAGE} MATCHES ...)

to

    if(LANGUAGE MATCHES ...)

However, `LANGUAGE` is a foreach() loop variable and not a normal
variable so auto-dereference does not occur.  Restore the explicit `${}`
syntax and use the new name of the loop variable that has changed since
then too.

Fixes: #16651

Refactoring in commit v3.6.0-rc1~72^2 (HDF5: Rework component searching
to correctly find HL for all bindings, 2016-05-12) renamed the language
loop variable used to construct the name of `HDF5_<LANG>_INCLUDE_DIR`
but forgot to update it in the `mark_as_advanced` call.  Fix it now.

Issue: #16651

Since commit v3.7.0-rc1~132^2 (CTestSVN: Fix segfault when
CTEST_UPDATE_VERSION_ONLY is enabled, 2016-09-12) we do not properly
extract svn log or externals.  After updating we erase the information
that was loaded before updating and can no longer log the changes
between revisions to extract authors.

Fix this by only loading the repository information once, whether needed
by `NoteOldRevision`, `NoteNewRevision`, or both.

Fixes: #12630, #16646

Fix the default values of `CMAKE_CUDA_FLAGS[_<CONFIG>]` on Windows to
make the host compiler flags match those produced for C++ by the
`Platform/Windows-MSVC` module.  This makes the flags consistent with
those used for C++.

Append to `CMAKE_CUDA_FLAGS` instead of overwriting it.

Fix the CUDA MinSizeRel configuration flags to avoid using the `-Os`
flag that nvcc does not support.

On Windows with MSVC-like host compilers we must honor the standard
libraries chosen by the `Platform/Windows-MSVC` module.  Otherwise C
code linked into the CUDA binary that expects to have these libraries
available may not link.

An executable using CUDA and C should link as CUDA.