LLVM/Clang 20, when invoked as `clang++ -E -c ...`, now warns:
warning: argument unused during compilation: '-c'
Drop the unnecessary `-c` flag. Also add a `-w` flag to suppress
warnings so their text is not parsed as predefines.
This variable define how the link step is done. Possible values are:
* DRIVER: the compiler is used as driver for the link step
* LINKER: the linker is used directly for the link step.
Apply the fix from commit 1ec6485c6a (Support duplicate object names in
large archives, 2014-04-16, v3.1.0-rc1~629^2) to the IPO-specific
archiving rules. Use "quick append" instead of "replace".
Fixes: #25675
Issue: #14874
Don't initialize the other CMAKE_<LANG>_COMPILER_PREDEFINES_COMMAND
variables.
The only language variant that is used is
CMAKE_CXX_COMPILER_PREDEFINES_COMMAND, and the other language variants
contained invalid, namely C++-specific commands.
Fixes: #23968
Add `COMPILE_WARNING_AS_ERROR` target property and supporting
`CMAKE_COMPILE_WARNING_AS_ERROR` variable.
`COMPILE_WARNING_AS_ERROR` is initialized by
`CMAKE_COMPILE_WARNING_AS_ERROR`. It is a boolean variable. If it is
true, it expands to a different flag depending on the compiler such that
any warnings at compile will be treated as errors.
Supports compiler ids that I could find a relevant flag for.
Divert LCC compiler as a new one, instead of treating it as GNU.
Since old times, Elbrus C/C++/Fortran Compiler (LCC) by MCST has been
passing checks for GNU compilers, so it has been identified as GNU.
Now, with intent of seriously upstreaming its support, it has been
added as a separate LCC compiler, and its version displays not a
supported GCC version, but LCC version itself (e.g. LCC 1.25.19 instead
of GNU 7.3.0).
This commit adds its support for detection, and also converts basically
every check like 'is this compiler GNU?' to 'is this compiler GNU or
LCC?'. The only places where this check is untouched, is where it
regards other platforms where LCC is unavailable (primarily non-Linux),
and where it REALLY differs from GNU compiler.
Note: this transition may break software that are already ported to
Elbrus, but hardly relies that LCC will be detected as GNU; still such
software is not known.
