This replaces all of the Apache blurbs at the start of each file with an
`# SPDX-License-Identifier: Apache-2.0` string. It also fixes existing
uses to be consistent in capitalization, and to be placed above any
copyright notices.
This removes nearly 3000 lines of boilerplate from the project (only
python files), which no developer cares to look at.
SPDX is in common use, particularly in the Linux kernel, and is the
recommended format for Meson's own `project(license: )` field
This also makes it more consistent with get_pkgconfig_variable() which
always return empty value instead of failing when the variable does not
exist. Linking that to self.required makes no sense and was never
documented any way.
We will still try to load `meson_options.txt` if `meson.options` doesn't
exist. Because there are some advantages to using `meson.options` even
with older versions of meson (such as better text editor handling)
we will not warn about the existence of a `meson.options` file if a
`meson_options.txt` file or symlink also exists.
The name `meson.options` was picked instead of alternative proposals,
such as `meson_options.build` for a couple of reasons:
1. meson.options is shorter
2. While the syntax is the same, only the `option()` function may be
called in meson.options, while, it may not be called in meson.build
3. While the two files share a syntax and elementary types (strings,
arrays, etc), they have different purposes: `meson.build` declares
build targets, `meson.options` declares options. This is similar to
the difference between C's `.c` and `.h` extensions.
As an implementation detail `Interpreter.option_file` has been removed,
as it is used exactly once, in the `project()` call to read the options,
and we can just calculate it there and not store it.
Fixes: #11176
"targetting" is verb-derived adjective, which sort-of-works here, but
makes the whole sentence awkward, because there's no verb. Let's just
use present simple.
Dylan Baker
Xavier Claessens
Zbigniew Jędrzejewski-Szmek
Eli Schwartz