docs: belatedly generate release notes for 1.9.0

Fixes: #14984

Author: eli-schwartz

docs/markdown/Release-notes-for-1.9.0.md

@@ -0,0 +1,133 @@
+---
+title: Release 1.9.0
+short-description: Release notes for 1.9.0
+...
+
+# New features
+
+Meson 1.9.0 was released on 24 August 2025
+## Array `.flatten()` method
+
+Arrays now have a `.flatten()` method, which turns nested arrays into a single
+flat array. This provides the same effect that Meson often does to arrays
+internally, such as when passed to most function arguments.
+
+## `clang-tidy`'s auto-generated targets correctly select source files
+
+In previous versions, the target would run `clang-tidy` on _every_ C-like source files (.c, .h, .cpp, .hpp). It did not work correctly because some files, especially headers, are not intended to be consumed as is.
+
+It will now run only on source files participating in targets.
+
+## Added Qualcomm's embedded linker, eld
+
+Qualcomm recently open-sourced their embedded linker.
+https://github.com/qualcomm/eld
+
+Meson users can now use this linker.
+
+## Added suffix function to the FS module
+
+The basename and stem were already available. For completeness, expose also the
+suffix.
+
+## Support response files for custom targets
+
+When using the Ninja backend, Meson can now pass arguments to supported tools
+through response files.
+
+In this release it's enabled only for the Gnome module, fixing calling
+`gnome.mkenums()` with a large set of files on Windows (requires
+Glib 2.59 or higher).
+
+## meson format now has a --source-file-path argument when reading from stdin
+
+This argument is mandatory to mix stdin reading with the use of editor config.
+It allows to know where to look for the .editorconfig, and to use the right
+section of .editorconfig based on the parsed file name.
+
+## Added license keyword to pkgconfig.generate
+
+When specified, it will add a `License:` attribute to the generated .pc file.
+
+## New experimental option `rust_dynamic_std`
+
+A new option `rust_dynamic_std` can be used to link Rust programs so
+that they use a dynamic library for the Rust `libstd`.
+
+Right now, `staticlib` crates cannot be produced if `rust_dynamic_std` is
+true, but this may change in the future.
+
+## Rust and non-Rust sources in the same target
+
+Meson now supports creating a single target with Rust and non Rust
+sources mixed together.  In this case, if specified, `link_language`
+must be set to `rust`.
+
+## Explicitly setting Swift module name is now supported
+
+It is now possible to set the Swift module name for a target via the
+*swift_module_name* target kwarg, overriding the default inferred from the
+target name.
+
+```meson
+lib = library('foo', 'foo.swift', swift_module_name: 'Foo')
+```
+
+## Top-level statement handling in Swift libraries
+
+The Swift compiler normally treats modules with a single source
+file (and files named main.swift) to run top-level code at program
+start. This emits a main symbol which is usually undesirable in a
+library target. Meson now automatically passes the *-parse-as-library*
+flag to the Swift compiler in case of single-file library targets to
+disable this behavior unless the source file is called main.swift.
+
+## Swift compiler receives select C family compiler options
+
+Meson now passes select few C family (C/C++/Obj-C/Obj-C++) compiler
+options to the Swift compiler, notably *-std=*, in order to improve
+the compatibility of C code as interpreted by the C compiler and the
+Swift compiler.
+
+NB: This does not include any of the options set in the target's
+c_flags.
+
+## Swift/C++ interoperability is now supported
+
+It is now possible to create Swift executables that can link to C++ or
+Objective-C++ libraries. To enable this feature, set the target kwarg
+_swift\_interoperability\_mode_ to 'cpp'.
+
+To import C++ code, specify a bridging header in the Swift target's
+sources, or use another way such as adding a directory containing a
+Clang module map to its include path.
+
+Note: Enabling C++ interoperability in a library target is a breaking
+change. Swift libraries that enable it need their consumers to enable
+it as well, as per [the Swift documentation][1].
+
+Swift 5.9 is required to use this feature. Xcode 15 is required if the
+Xcode backend is used.
+
+```meson
+lib = static_library('mylib', 'mylib.cpp')
+exe = executable('prog', 'main.swift', 'mylib.h', link_with: lib, swift_interoperability_mode: 'cpp')
+```
+
+[1]: https://www.swift.org/documentation/cxx-interop/project-build-setup/#vending-packages-that-enable-c-interoperability
+
+## Support for MASM in Visual Studio backends
+
+Previously, assembling `.masm` files with Microsoft's Macro Assembler is only
+available on the Ninja backend. This now also works on Visual Studio backends.
+
+Note that building ARM64EC code using `ml64.exe` is currently unimplemented in
+both of the backends. If you need mixing x64 and Arm64 in your project, please
+file an issue on GitHub.
+
+## Limited support for WrapDB v1
+
+WrapDB v1 has been discontinued for several years, Meson will now print a
+deprecation warning if a v1 URL is still being used. Wraps can be updated to
+latest version using `meson wrap update` command.
+