Clarify a couple error messages

src/graphics/material.cpp

@@ -291,7 +291,7 @@ Material::Material(const XMLNode *node, int index, bool deprecated)
 
     if (m_disable_z_write && !m_alpha_blending && !m_add)
     {
-        Log::warn("material", "Disabling writes to z buffer only makes sense when compositing is blending or additive");
+        Log::warn("material", "Disabling writes to z buffer only makes sense when compositing is blending or additive (for %s)", m_texname.c_str());
         m_disable_z_write = false;
     }
 

src/tracks/track.cpp

@@ -476,8 +476,8 @@ void Track::getMusicInformation(std::vector<std::string>&       filenames,
             m_music.push_back(mi);
         else
             Log::warn("track",
-                      "Music information file '%s' not found - ignored.\n",
-                      filenames[i].c_str());
+                      "Music information file '%s' not found for track '%s' - ignored.\n",
+                      filenames[i].c_str(), m_name.c_str());
 
     }   // for i in filenames