Change #254656

Comments

cmake: silence useless compiler warnings triggered by the FASTBuild generator
Silencing all of these:
```
11>/tmp/_fbuild.tmp/0x0752c383/core_2/70816E19/krb5_sspi.c:1:5: error: this style of line directive is a GNU extension [-Werror,-Wgnu-line-marker]
    1 | # 1 "<built-in>"
      |     ^
/path/to/curl/lib/vauth/krb5_sspi.c:29:6: error: this style of line directive is a GNU extension [-Werror,-Wgnu-line-marker]
   29 | # 26 "/path/to/curl/lib/vauth/krb5_sspi.c"
      |      ^
[...]
```

FASTBuild is slightly faster than Ninja in basic (single-machine, build
from scratch) cases (and can be more faster in other build cases). It
doesn't support unity builds. Maybe it can bring slightly better
performance to non-unity cmake CI jobs, in jobs having an 'install
prereq' phase already, and installing the fastbuild package being faster
than this gain. It overall seems marginal if any in curl CI. At least
for now. But it doesn't hurt if it works, and may be useful for some.

Requires CMake 4.2+.

That said this workaround may have a better place within CMake.

Refs:
https://www.kitware.com/cmake-fastbuild-distributed-cached-and-fast/
https://cmake.org/cmake/help/latest/generator/FASTBuild.html
https://github.com/fastbuild/fastbuild
https://fastbuild.org/docs/home.html

Closes #20230

Changed files

• CMake/PickyWarnings.cmake