vendor libsecret

The libsecret-rs crate is unmaintained, so I'm vendoring it for
now. Bumping the glib version turned out to be enough.

The exact process I used was:
1. Cloning the repository
2. Making changes
3. `cargo build` to ensure it works
4. `cargo package --no-verify` (b/c it tries to build all crates
separately instead of the entire workspace as a whole)
5. `mkdir libsecret/sys -p`
6. `tar --strip-components 1 -C libsecret -xvf ../libsecret-rs/target/package/libsecret-0.6.0.crate`
7. `tar --strip-components 1 -C libsecret/sys -xvf ../libsecret-rs/target/package/libsecret-sys-0.6.0.crate`

Then `Cargo.toml` is modified to ensure the libsecret and its `-sys`
crate build out of my vendored sources.

In the future, if I gain maintainership of the `libsecret` crate, I
could just revert this commit to make it point back to the upstream.

1 files changed, 18 insertions, 0 deletions

diff --git a/libsecret/sys/build.rs b/libsecret/sys/build.rs
new file mode 100644
index 0000000..fc0010a
--- /dev/null
+++ b/libsecret/sys/build.rs
@@ -0,0 +1,18 @@
+// Generated by gir (https://github.com/gtk-rs/gir @ 4dd714f7f3b1)
+// from
+// from gir-files (https://github.com/gtk-rs/gir-files.git @ b9db716f1bb7)
+// DO NOT EDIT
+
+#[cfg(not(docsrs))]
+use std::process;
+
+#[cfg(docsrs)]
+fn main() {} // prevent linking libraries to avoid documentation failure
+
+#[cfg(not(docsrs))]
+fn main() {
+    if let Err(s) = system_deps::Config::new().probe() {
+        println!("cargo:warning={s}");
+        process::exit(1);
+    }
+}