gstreamer: Manually implement StateChange::get_name on < v1_14

By setting the version to 1.8 and using `manual = true` an unconditional
trait implementation calling get_name is generated, while the
autogenerated version is omitted.

gstreamer/Gir.toml

@@ -43,7 +43,6 @@ generate = [
     "Gst.SchedulingFlags",
     "Gst.SeekType",
     "Gst.State",
-    "Gst.StateChange",
     "Gst.StreamError",
     "Gst.StreamStatusType",
     "Gst.StreamType",
@@ -1631,6 +1630,16 @@ status = "generate"
     # confusing return type
     ignore = true
 
+[[object]]
+name = "Gst.StateChange"
+status = "generate"
+    [[object.function]]
+    name = "get_name"
+    # Manual function for < v1_14:
+    manual = true
+    # Always generate the trait, without version constraint:
+    version = "1.8"
+
 [[object]]
 name = "Gst.StateChangeReturn"
 status = "generate"

gstreamer/src/enums.rs

@@ -684,4 +684,36 @@ impl StateChange {
             StateChange::__Unknown(value) => State::__Unknown(value & 0x7),
         }
     }
+
+    pub fn get_name<'a>(self) -> &'a str {
+        cfg_if::cfg_if! {
+            if #[cfg(feature = "v1_14")] {
+                // This implementation is autogenerated on 1.14 and up
+                use std::ffi::CStr;
+                unsafe {
+                    CStr::from_ptr(
+                        ffi::gst_state_change_get_name(self.to_glib())
+                            .as_ref()
+                            .expect("gst_state_change_get_name returned NULL"),
+                    )
+                    .to_str()
+                    .expect("gst_state_change_get_name returned an invalid string")
+                }
+            } else {
+                match self {
+                    Self::NullToReady => "NULL->READY",
+                    Self::ReadyToPaused => "READY->PAUSED",
+                    Self::PausedToPlaying => "PAUSED->PLAYING",
+                    Self::PlayingToPaused => "PLAYING->PAUSED",
+                    Self::PausedToReady => "PAUSED->READY",
+                    Self::ReadyToNull => "READY->NULL",
+                    Self::NullToNull => "NULL->NULL",
+                    Self::ReadyToReady => "READY->READY",
+                    Self::PausedToPaused => "PAUSED->PAUSED",
+                    Self::PlayingToPlaying => "PLAYING->PLAYING",
+                    _ => "Unknown state return",
+                }
+            }
+        }
+    }
 }