Add cmake option BACKWARD_INSTALL to allow backward-cpp built as a subproject but not be installed

[zhao-shihan]

No description provided.

[lahwaacz]

This should not be done with yet another option, but by changing the way you use the subproject:

add_subdirectory (path-to-backward-cpp EXCLUDE_FROM_ALL)

See https://stackoverflow.com/a/64900982

[zhao-shihan]

This should not be done with yet another option, but by changing the way you use the subproject:

add_subdirectory (path-to-backward-cpp EXCLUDE_FROM_ALL)

See https://stackoverflow.com/a/64900982

I certainly agree! However, in many cases FetchContent is much convenient than raw add_subdirectory. But unlike add_subdirectory, FetchContent have no EXCLUDE_FROM_ALL until CMake 3.28, which is a pretty new release (Debian 12 has just 3.25). Therefore, add this option might help old toolchains.

Libraries like fmt and yaml-cpp also provide corresponding XYZ_INSTALL. It does not harm in practice.