Merge-request: !3953

Merge-request: !3941

Merge-request: !3937

Merge-request: !3916

Merge-request: !3939

Fix the `COMPILE_LANGUAGE/CXX_COMPILER_ID` variant of the example to
have the same meaning as the `COMPILE_LANG_AND_ID` variant.  The
inconsistency was introduced by commit 808b8180 (Genex: CompileLang
and CompileLangAndId now match against a list of ids, 2019-05-30,
v3.15.0-rc1~11^2~1).

Fixes: #19862

Merge-request: !3928

Teach the Makefile generator to scan the implicit dependencies of PCH
creation.  When a header named by `target_precompile_headers` changes
the corresponding PCH must be rebuilt and all consumers recompiled.

Fixes: #19830

Merge-request: !3927

Fixes: #18098 #18470 #18520

When generating `IMPORTED_LINK_INTERFACE_LANGUAGES`, do not treat the
entries as target names.

Fixes: #19846

Merge-request: !3925

Fixes: #19839

Merge-request: !3922

Merge-request: !3921

Ensure that we preserve the `CMAKE_Swift_COMPILER_TARGET` variable to
use cross-compilation for testing the Swift compiler if appropriate.

Merge-request: !3920

Merge-request: !3915

Merge-request: !3918

Merge-request: !3919

Some unset calls were added by commit 079b8e29 (Clang: prefer lld-link
over link.exe, 2019-07-11, v3.16.0-rc1~161^2~2) but they are unnecessary
since commit 3a82ef78 (CMakeFindBinUtils: Rename and unset variables
for additional names, 2019-07-23, v3.16.0-rc1~332^2~2).
Suggested-by: Norbert Lange <nolange79@gmail.com>

Issue: #19838

Merge-request: !3912

Merge-request: !3911

Since commit 4ca0526f (cmake: Pass -S and -B into PreLoad.cmake and -C
scripts, 2019-08-20, v3.16.0-rc1~195^2) the value of `CMAKE_SOURCE_DIR`
is the source directory rather than the current working directory.
This was correct on its own, but the place storing that value is also
used as the base for relative paths specified on the command line.
The latter should of course be relative to the current working
directory.

The fix is to switch to use a full path internally, unless a full path
is already specified.  Add tests for the behaviour of `-C` under these
four circumstances:

    {with -S, without -S} x {full path, relative path}

Fixes: #19827

The HIP clang makes 2 passes when compiling HIP programs: the DEVICE
pass and the HOST pass.  For openmp, the `-fopenmp` option is only
passed to the HOST compilation pass.  Therefore, the small test that
CMake uses for OpenMP detection fails to compile, and CMake reports
failure to detect OpenMP support in the compiler.  The suggested
solution is to add check for `__HIP_DEVICE_COMPILE__` macro defined by
HIP clang for the DEVICE pass to the OpenMP detection test.

Merge-request: !3910

Distro maintainers who are building from Git with patches added on
may want to disable the automatic Git suffixing, as it does not
provide any useful information and simply confuses the end user.
Add an undocumented CMake_VERSION_NO_GIT variable to disable this.

Update the approach from commit fe2c558b (CMakeVersion: Preserve Git
information during 'git archive', 2019-07-25, v3.16.0-rc1~337^2) to
prefer `export-subst` information.  This will allow exported source
trees to be imported into unrelated Git repositories while still using
the original upstream CMake commit information.

Merge-request: !3909

VS 2019 now distributes this additional runtime DLL with its `14.2x`
toolsets.

Fixes: #19829