Revert commit 74b1c9fc8e (Explicitly specify language flag when source
LANGUAGE property is set, 2020-06-01, v3.19.0-rc1~722^2) and the lookup
tables from its two immediate ancestors. The purpose of that change was
to convert an explicit `LANGUAGE` source file property into an explicit
language specification compiler flag like `-x c`. This seems reasonable
since the property is documented as meaning "indicate what programming
language the source file is". It is also needed to help compilers deal
with non-standard source file extensions they don't recognize.
However, some projects have been setting `LANGUAGE C` on `.S` assembler
source files to mean "use the C compiler". Passing `-x c` for them
breaks the build because the `.S` sources are not written in C. These
projects should be updated to use `enable_language(ASM)`, for which
CMake often chooses the C compiler as the assembler when using
toolchains that support it (which would have to be the case for projects
using the approach).
Revert the change for now to preserve the old behavior for such projects.
We can re-introduce it with a policy in a future version of CMake.
Fixes: #21469
Issue: #14516, #20716
Since commit 3b547e2e4b (VS: Simplify logic adding source file C/C++
language flag to MSVC, 2020-05-15, v3.18.0-rc1~139^2~1) we only add a
per-source language selection flag when the source file extension does
not match the compiler's default. This approach breaks when a project
adds a target-wide `-TP` flag.
Although such projects likely did not work with non-VS generators, we
did support them before in Visual Studio generators. Add a special case
to tolerate such flags again.
Fixes: #21005
Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Brad King