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, 25 insertions, 0 deletions

diff --git a/libsecret/src/enums.rs b/libsecret/src/enums.rs
new file mode 100644
index 0000000..59de400
--- /dev/null
+++ b/libsecret/src/enums.rs
@@ -0,0 +1,25 @@
+use glib::error::ErrorDomain;
+use glib::translate::*;
+
+use crate::Error;
+
+impl ErrorDomain for Error {
+    fn domain() -> glib::Quark {
+        unsafe { from_glib(ffi::secret_error_get_quark()) }
+    }
+
+    fn code(self) -> i32 {
+        self.into_glib()
+    }
+
+    fn from(code: i32) -> Option<Self> {
+        match code {
+            ffi::SECRET_ERROR_PROTOCOL => Some(Self::Protocol),
+            ffi::SECRET_ERROR_IS_LOCKED => Some(Self::IsLocked),
+            ffi::SECRET_ERROR_NO_SUCH_OBJECT => Some(Self::NoSuchObject),
+            ffi::SECRET_ERROR_ALREADY_EXISTS => Some(Self::AlreadyExists),
+            ffi::SECRET_ERROR_INVALID_FILE_FORMAT => Some(Self::InvalidFileFormat),
+            value => Some(Self::__Unknown(value)),
+        }
+    }
+}