Segfault on glfwTerminate

[recallmenot]

I have found a bug in GLFW when using ANGLE.
When calling glfwTerminate() (with a valid and working context), a segfault occurs.
I’ve run a gdb backtrace on it:

#0  0x00007ffff72fef37 in _XSend () from /usr/lib/libX11.so.6
#1  0x00007ffff72f77d9 in XQueryExtension () from /usr/lib/libX11.so.6
#2  0x00007ffff6de7dd8 in ?? () from /usr/lib/libGLX.so.0
#3  0x00007ffff6dea2f9 in ?? () from /usr/lib/libGLX.so.0
#4  0x00007ffff6dea799 in glXDestroyPbuffer () from /usr/lib/libGLX.so.0
#5  0x00007ffff79672b7 in rx::DisplayGLX::terminate() ()
   from /home/a/libraries/angle/out/Release/libGLESv2.so
#6  0x00007ffff77bbd90 in egl::Display::terminate(egl::Thread*, egl::Display::TerminateReason) ()
   from /home/a/libraries/angle/out/Release/libGLESv2.so
#7  0x00007ffff760fb92 in egl::Terminate(egl::Thread*, egl::Display*) ()
   from /home/a/libraries/angle/out/Release/libGLESv2.so
#8  0x00007ffff7611678 in EGL_Terminate () from /home/a/libraries/angle/out/Release/libGLESv2.so
#9  0x00007ffff7c73ec2 in eglTerminate () from /home/a/libraries/angle/out/Release/libEGL.so
#10 0x000055555559cc93 in _glfwTerminateEGL ()
#11 0x000055555558e53a in _glfwTerminateX11 ()
#12 0x000055555557be24 in terminate ()
#13 0x000055555557cea8 in glfwTerminate ()
#14 0x000055555557a083 in shutdown () at esshader.c:503
#15 0x000055555557a785 in main (argc=1, argv=0x7fffffffe2b8) at esshader.c:72

ANGLE was compiled from source, so was glfw.
Calling glfwDestroyWindow(window) does not improve this behavior.

I’m using GLFW to load Angle:

#define GLFW_INCLUDE_ES3
#include <GLFW/glfw3.h>

And to initialize I’m doing this:

	if (!glfwInit()) {
		die("Unable to initialize GLFW.\n");
	}

	glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
	glfwWindowHint(GLFW_CONTEXT_CREATION_API, GLFW_EGL_CONTEXT_API);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);

	if (!(window = glfwCreateWindow(width, height, "esshader", monitor, NULL))) {
		glfwTerminate();
		die("Unable to create GLFW window.\n");
	}

	glfwMakeContextCurrent(window);

@mmozeiko over on the glfw discourse forum found the solution:
The fix for NVIDIA EGL having the same issue was to move _glfwTerminateEGL() but this breaks ANGLE.

glfw/src/x11_init.c

Line 1641 in 3eaf125

_glfwTerminateEGL();

Moving it back to where it was before (below if (_glfw.x11.im) { ... }, nowadays L1589) eliminates the error; GLFW can then shut down fine with ANGLE.
Not trying to break NVIDIA EGL again either, a fix would need to be run-time, either detecting NVIDIA or ANGLE but I have no idea how to accomplish that.

If anyone has an idea, I could then finish up the PR.