Update README.md

Added glfw build instructions

README.md

@@ -106,6 +106,34 @@ Steps for building/rebuilding the C-MEX S-Function code. These instructions are
 - ***Code generation*** - The MuJoCo Plant block supports code generation (Simulink Coder) and monitor and tune for host target. Refer to mj_monitorTune.slx for more info.
 - ***Performance improvement*** - In case you want to reduce the mask initialization overhead, you can directly use the underlying S-Function. Select the MuJoCo Plant block and Ctrl+U to look under the subsystem mask. Make sure to call the initialization functions (whenever the MJCF XML model changes).
 
+## Bugs/Workarounds
+### GLFW 
+
+In case MATLAB crashes while running getting started model and you see the following lines in stack trace,
+
+`#10 0x00007fdaf8619f40 in glfwCreateWindow () at /lib/x86_64-linux-gnu/libglfw.so.3`
+
+`#11 0x00007fdaf8675c4d in MujocoGUI::initInThread(offscreenSize*, bool)`,
+
+Updating glfw could fix the issue.
+
+Building glfw from source ([glfw main - commit id](https://github.com/glfw/glfw/tree/46cebb5081820418f2a20f3e90b07f9b1bd44b42)) and installing fixed this issue for me,
+- sudo apt remove libglfw3 libglfw3-dev # Remove existing glfw
+- mkdir ~/glfwupdated
+- cd ~/gflwupdated
+- git clone git@github.com:glfw/glfw.git
+- sudo apt install cmake-qt-gui
+- cmake-gui
+- Set the source directory to the root of cloned repo
+- mkdir build in the cloned repo
+- Set the build directory
+- In Cmake Gui settings - Select "BUILD_SHARED_LIBS" as well
+- Configure and then generate
+- Open a terminal in the build directory and run $make in terminal
+- Once build goes through without any error, run $make install in terminal
+- sudo ldconfig (to refresh linker cache)
+- Follow the build instructions for mujoco-simulink-blockset
+
 ## License
 
 The license is available in the license.txt file within this repository.