[PATCH v2 4/5] wmphoto: Implement WMP decoder using jxrlib.

[Esme Povirk (they/them)]

+static JXR_ERR wmp_stream_Read(struct WMPStream *iface, void *buf, size_t len)
+{
+    struct wmp_decoder *This = impl_from_WMPStream(iface);
+    ULONG count;
+    if (FAILED(stream_read(This->stream, buf, len, &count)))
+        return WMP_errFileIO;
+    return WMP_errSuccess;
+}

This might silently return fewer bytes than requested.

+#ifdef SONAME_LIBJXRGLUE
+        return wmp_decoder_create(info, result);
+#else
+    {
+        WARN("jxrlib support not compiled in!\n");
+        return E_NOINTERFACE;
+    }
+#endif

I would use an ERR for a missing dependency, not a WARN.