Reporting: Log when vertex count truncated.

GPU/GLES/DrawEngineGLES.cpp

@@ -373,8 +373,11 @@ void DrawEngineGLES::DoFlush() {
 
 		// TODO: Split up into multiple draw calls for GLES 2.0 where you can't guarantee support for more than 0x10000 verts.
 #if defined(MOBILE_DEVICE)
-		if (vertexCount > 0x10000 / 3)
-			vertexCount = 0x10000 / 3;
+		constexpr int vertexCountLimit = 0x10000 / 3;
+		if (vertexCount > vertexCountLimit) {
+			WARN_LOG_REPORT_ONCE(manyVerts, G3D, "Truncating vertex count from %d to %d", vertexCount, vertexCountLimit);
+			vertexCount = vertexCountLimit;
+		}
 #endif
 
 		SoftwareTransform swTransform(params);