The `CMAKE_REQUIRED_FLAGS` variable, used by the various entry points to
`cmake_check_source_{compiles,runs}`, specifies that flags shall not be
separated by semicolons. This is because the way in which it is passed
to the child `cmake` process means that, when considered as a list (with
semicolon separated items), only the first item is actually used as
compile flags, with any additional items actually seen as arguments to
the child `cmake` process. While this usage is unsupported, if invoked
accidentally, flags starting with `-W` were silently ignored by CMake.
However, CMake 4.4 newly complains about unrecognized warning
categories, which means that uses which were silently broken now result
in a hard error.
In the longer term, it would be helpful to introduce a policy to repair
improper use of semicolons in `CMAKE_REQUIRED_FLAGS` in order to do what
the user probably meant. However, for various reasons, we do not want to
introduce a policy to CMake 4.4 at this time, and anyway, the policy
won't help users that haven't enabled it. Therefore, alter the 'check
source' functions to detect arguments being passed to `cmake` rather
than the compiler, and remove any such that start with `-W`. This
removes any arguments that newly cause errors starting with CMake 4.4,
while not otherwise altering behavior in case any users were abusing
this implementation quirk.
Strictly speaking, this means that users can no longer abuse this quirk
to alter CMake's diagnostics. However, the only case in which this
should be observable is if the user is already abusing the quirk to
inject their own CMake logic into the CMake-provided test projects.
Since this was never supported, anyone doing that can keep the pieces.
Issue: #27901Fixes: #27893
Preserve backslashes in arguments passed to macros by re-escaping
them before substituting in the macro body, where they will be
parsed again.
Fixes: #19281, #22157, #23641, #25803, #27645, #20891
`lfortran` < 1.24 uses `fccn`, a Fortran-to-C converter that
incorrectly handles long filenames that are more than 128 characters
long; so to check if Fortran can compile something, CMake must be
run in binary directory that has a name of less that 35 characters long.
It is ok for typical runs line `cmake -S . -B build` or `cmake ..`,
but does not work with usual CDash dashboard testing paths.
All this is not a problem for modern LCC >= 1.24.
Cases for `CheckSource{Compiles,Runs}` and `Check{Compiler,Linker}Flag`
cover the modules with the language as a parameter, not the
language-specific modules.
Fix the language checks added by commit 90dead024c (CheckCompilerFlag:
unified way to check compiler flags per language, 2020-09-25,
v3.19.0-rc1~88^2), commit 10ae907de0 (CheckSoureCompiles: Add a unified
way to check if a source compiles, 2020-09-14, v3.19.0-rc1~118^2~1), and
commit 357e2ef429 (CheckSoureRuns: Add a unified way to check if a
source runs, 2020-09-14, v3.19.0-rc1~118^2) to work when variables of
the language names are set.
Fixes: #21500
The conversion of Check<Lang>CompilerFlag, SourceCompiles, and
SourceRuns over to the new functions has the possibility of breaking
projects that had functions with those existing names.
To reduce the possibility of collisions we now have all the
legacy code call functions that start with `cmake_`, and users
will need to explicitly include the new modules to get the
non-prefixed versions
Fixes: #21359
Matthew Woehlke
Alex Reinking
Joseph Snyder
AJIOB
Hanna Rusakovich
makise-homura
Evan Wilde
Brad King
Robert Maynard