x11 window and opengl initialization and drawing of basic quad

shaders/board_f.glsl

@@ -0,0 +1,6 @@
+#version 330 core
+out vec4 FragColor;
+
+void main() {
+  FragColor = vec4(240.f/255.f, 235.f/255.f, 227.f/255.f, 1.0);
+}

shaders/board_v.glsl

@@ -0,0 +1,6 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+
+void main() {
+  gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+}