Rename doc/manual{src -> source}

This is needed to avoid this
https://github.com/mesonbuild/meson/issues/13774 when we go back to
making our subproject directory `src`.

doc/manual/source/release-notes/rl-1.0.md

@@ -0,0 +1,68 @@
+# Release 1.0 (2012-05-11)
+
+There have been numerous improvements and bug fixes since the previous
+release. Here are the most significant:
+
+  - Nix can now optionally use the Boehm garbage collector. This
+    significantly reduces the Nix evaluator’s memory footprint,
+    especially when evaluating large NixOS system configurations. It can
+    be enabled using the `--enable-gc` configure option.
+
+  - Nix now uses SQLite for its database. This is faster and more
+    flexible than the old *ad hoc* format. SQLite is also used to cache
+    the manifests in `/nix/var/nix/manifests`, resulting in a
+    significant speedup.
+
+  - Nix now has an search path for expressions. The search path is set
+    using the environment variable `NIX_PATH` and the `-I` command line
+    option. In Nix expressions, paths between angle brackets are used to
+    specify files that must be looked up in the search path. For
+    instance, the expression `<nixpkgs/default.nix>` looks for a file
+    `nixpkgs/default.nix` relative to every element in the search path.
+
+  - The new command `nix-build --run-env` builds all dependencies of a
+    derivation, then starts a shell in an environment containing all
+    variables from the derivation. This is useful for reproducing the
+    environment of a derivation for development.
+
+  - The new command `nix-store --verify-path` verifies that the contents
+    of a store path have not changed.
+
+  - The new command `nix-store --print-env` prints out the environment
+    of a derivation in a format that can be evaluated by a shell.
+
+  - Attribute names can now be arbitrary strings. For instance, you can
+    write `{ "foo-1.2" = …; "bla bla" = …; }."bla
+                    bla"`.
+
+  - Attribute selection can now provide a default value using the `or`
+    operator. For instance, the expression `x.y.z or e` evaluates to the
+    attribute `x.y.z` if it exists, and `e` otherwise.
+
+  - The right-hand side of the `?` operator can now be an attribute
+    path, e.g., `attrs ?
+                    a.b.c`.
+
+  - On Linux, Nix will now make files in the Nix store immutable on
+    filesystems that support it. This prevents accidental modification
+    of files in the store by the root user.
+
+  - Nix has preliminary support for derivations with multiple outputs.
+    This is useful because it allows parts of a package to be deployed
+    and garbage-collected separately. For instance, development parts of
+    a package such as header files or static libraries would typically
+    not be part of the closure of an application, resulting in reduced
+    disk usage and installation time.
+
+  - The Nix store garbage collector is faster and holds the global lock
+    for a shorter amount of time.
+
+  - The option `--timeout` (corresponding to the configuration setting
+    `build-timeout`) allows you to set an absolute timeout on builds —
+    if a build runs for more than the given number of seconds, it is
+    terminated. This is useful for recovering automatically from builds
+    that are stuck in an infinite loop but keep producing output, and
+    for which `--max-silent-time` is ineffective.
+
+  - Nix development has moved to GitHub
+    (<https://github.com/NixOS/nix>).