[client] renderers: remove alert handling

client/renderers/EGL/shader/alert.frag

@@ -1,12 +0,0 @@
-#version 300 es
-
-in  highp vec2 uv;
-in  highp vec2 sz;
-out highp vec4 color;
-
-uniform sampler2D sampler1;
-
-void main()
-{
-  color = texelFetch(sampler1, ivec2(uv * sz), 0);
-}

client/renderers/EGL/shader/alert.vert

@@ -1,24 +0,0 @@
-#version 300 es
-
-layout(location = 0) in vec3 vertexPosition_modelspace;
-layout(location = 1) in vec2 vertexUV;
-
-uniform vec2  screen;
-uniform ivec2 size;
-uniform vec4  color;
-
-out highp vec2 uv;
-out highp vec2 sz;
-out highp vec4 c;
-
-void main()
-{
-  sz = vec2(size) + 0.5;
-
-  gl_Position.xyz = vertexPosition_modelspace;
-  gl_Position.w   = 1.0;
-  gl_Position.xy *= screen.xy * sz;
-
-  uv = vertexUV;
-  c  = color;
-}

client/renderers/EGL/shader/alert_bg.frag

@@ -1,9 +0,0 @@
-#version 300 es
-
-in  highp vec4 c;
-out highp vec4 color;
-
-void main()
-{
-  color = c;
-}