Providing a file or custom_target to link_args

[mitchgrout]

In the embedded space it is pretty common to have a linker-script file that is used when generating the final executable. For example, this might be stored as target.ld. It would be convenient to be able to write the following code:

target = fs.copyfile('target.ld')
executable(..., link_args: ['-T', target])

as otherwise providing the raw target.ld argument fails due to it not being present in the build directory.

You can currently get around this limitation by replacing target with

target = meson.current_source_dir() / 'target.ld'

but that feels antithetical to all of mesons design choices. At a glance this also looks like it should work:

target = fs.copyfile('target.ld').full_path()

however since fs.copyfile returns a custom_target, this will effectively prevent target.ld from ever being copied, and will cause the linker to fail complaining that target.ld is not found.