This is a layering violation, we're relying on the way the interpreter
handles keyword arguments. Instead, pass them as free variables,
destructuring in the interpreter
They passed the arguments in the wrong order, so the version parsed as the
message and the message parsed as a version.
While we are at it, pass the location node in too.
This replaces the absolute hack of using
```
install_subdir('nonexisting', install_dir: 'share')
```
which requires you to make sure you don't accidentally or deliberately
have a completely different directory with the same name in your source
tree that is full of files you don't want installed. It also avoids
splitting the name in two and listing them in the wrong order.
You can also set the install mode of each directory component by listing
them one at a time in order, and in fact create nested structures at
all.
Fixes#1604
Properly fixes#2904
Currently, EnvironmentVariablesObject is a strange
holder-that's-not-a-holder. This has implicaitons for things that expect
to get an EnvironmentVariables object, as we can't automatically
unholder it, and instead have to to manually do so. Now we can
automatically unholder it, which makes everything much nicer.
This commit introduces a new type of `HoldableObject`: The
`SecondLevelHolder`. The primary purpose of this class is
to handle cases where two (or more) `HoldableObject`s are
stored at the same time (with one default object). The
best (and currently only) example here is the `BothLibraries`
class.
As a side-effect from #8885 `find_program()` returns now `Executable`
objects when `meson.override_find_program` is called with an
executable target. To resolve this conflict the missing methods
from `ExternalProgram` are added to `BuildTarget`.
Remove an unused method (that didn't work before this series), and
remove the ability to pass a Generator to the GeneratedListHolder, it's
never used and it's weird and not the way Meson generally works now.
While we're here, finish the type annotations.