structure: Manually bind GST_SERIALIZE_FLAG_STRICT

As the flag changes the nullability of `gst_structure_serialize()` and
adding a new C function is apparently too much of a hassle for C
developers, add a new `serialize_strict()` function here that always
sets this flag and can fail.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1368>

gstreamer/Gir.toml

@@ -32,7 +32,6 @@ generate = [
     "Gst.PromiseResult",
     "Gst.QOSType",
     "Gst.SchedulingFlags",
-    "Gst.SerializeFlags",
     "Gst.StreamStatusType",
     "Gst.StreamType",
     "Gst.StructureChangeType",
@@ -2153,6 +2152,15 @@ status = "generate"
     name = "none"
     ignore = true
 
+[[object]]
+name = "Gst.SerializeFlags"
+status = "generate"
+    [[object.member]]
+    name = "strict"
+    # Changes nullability of gst_structure_serialize() so moved to a
+    # separate function instead
+    ignore = true
+
 [[object]]
 name = "Gst.StackTraceFlags"
 status = "generate"

gstreamer/src/structure.rs

@@ -744,6 +744,26 @@ impl StructureRef {
         unsafe { from_glib_full(ffi::gst_structure_serialize(&self.0, flags.into_glib())) }
     }
 
+    #[cfg(feature = "v1_24")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "v1_24")))]
+    #[doc(alias = "gst_structure_serialize")]
+    pub fn serialize_strict(
+        &self,
+        flags: crate::SerializeFlags,
+    ) -> Result<glib::GString, glib::BoolError> {
+        unsafe {
+            let res = ffi::gst_structure_serialize(
+                &self.0,
+                flags.into_glib() | ffi::GST_SERIALIZE_FLAG_STRICT,
+            );
+            if res.is_null() {
+                Err(glib::bool_error!("Failed to serialize structure to string"))
+            } else {
+                Ok(from_glib_full(res))
+            }
+        }
+    }
+
     #[doc(alias = "gst_structure_foreach")]
     pub fn foreach<F: FnMut(glib::Quark, &glib::Value) -> std::ops::ControlFlow<()>>(
         &self,