[client] use cmake to generate renderers/fonts/clipboards headers/code

This is in preperation of cmake options to enable/disable various
functionallity.

client/renderers/EGL/shader/splash_bg.vert

@@ -0,0 +1,17 @@
+#version 300 es
+
+layout(location = 0) in vec3 vertexPosition_modelspace;
+
+uniform float alpha;
+
+out highp vec3  pos;
+out highp float a;
+
+void main()
+{
+  gl_Position.xyz = vertexPosition_modelspace; 
+  gl_Position.w   = 1.0;
+
+  pos = vertexPosition_modelspace;
+  a   = alpha;
+}