Add options to specify linker tool

Offer the capability, through variable `CMAKE_LINKER_TYPE`, as well as
the target property `LINKER_TYPE` to specify which linker must be used.

The implementation of this capability is specified by variables specific
to the language and linker type: `CMAKE_<LANG>_USING_LINKER_<TYPE>`.
Some definitions are provided as part of `CMake`.

For example, to select the `LLVM` linker rather than the standard one,
the type `LLD` should be specified through the variable `CMAKE_LINKER_TYPE`.
And, on `Apple`, `Linux` and some environments on `Windows`, the variable
`CMAKE_<LANG>_USING_LINKER_LLD` has value `-fuse-ld=lld`. And for `Windows`
environments  based on `MSVC`, where the linker is used directly, the tool
`lld-link.exe` will be used rather than `link.exe`.

Fixes: #19174, #24254, #24990

1 files changed, 26 insertions, 0 deletions

diff --git a/Help/prop_tgt/LINKER_TYPE.rst b/Help/prop_tgt/LINKER_TYPE.rst
new file mode 100644
index 0000000..90a663d
--- /dev/null
+++ b/Help/prop_tgt/LINKER_TYPE.rst
@@ -0,0 +1,26 @@
+LINKER_TYPE
+-----------
+
+.. versionadded:: 3.29
+
+Specify which linker will be used for the link step. The property value may use
+:manual:`generator expressions <cmake-generator-expressions(7)>`.
+
+.. code-block:: cmake
+
+  add_library(lib1 SHARED ...)
+  set_property(TARGET lib1 PROPERTY LINKER_TYPE LLD)
+
+This specifies that ``lib1`` should use linker type ``LLD`` for the link step.
+The implementation details will be provided by the variable
+:variable:`CMAKE_<LANG>_USING_LINKER_<TYPE>` with ``<TYPE>`` having the value
+``LLD``.
+
+This property is not supported on :generator:`Green Hills MULTI` and
+:generator:`Visual Studio 9 2008` generators.
+
+.. note::
+  It is assumed that the linker specified is fully compatible with the standard
+  one. CMake will not do any options translation.
+
+.. include:: ../variable/LINKER_PREDEFINED_TYPES.txt