be explicit about shaders outputting srgb

This helps correct the color brightness on windows

src/gliumwindows.rs

@@ -140,7 +140,7 @@ impl TerminalWindow {
             let mut_loop = event_loop.event_loop.borrow_mut();
 
             glium::Display::new(window, pref_context, &*mut_loop)
-                        .map_err(|e| format_err!("{:?}", e))?
+                .map_err(|e| format_err!("{:?}", e))?
         };
         let window_id = display.gl_window().id();
         let window_position = display.gl_window().get_position();

src/opengl/render.rs

@@ -370,7 +370,17 @@ impl Renderer {
             f32::from(height),
         )?;
 
-        let program = glium::Program::from_source(facade, VERTEX_SHADER, FRAGMENT_SHADER, None)?;
+        let source = glium::program::ProgramCreationInput::SourceCode {
+            vertex_shader: VERTEX_SHADER,
+            fragment_shader: FRAGMENT_SHADER,
+            outputs_srgb: true,
+            tessellation_control_shader: None,
+            tessellation_evaluation_shader: None,
+            transform_feedback_varyings: None,
+            uses_point_size: false,
+            geometry_shader: None,
+        };
+        let program = glium::Program::new(facade, source)?;
 
         let atlas = RefCell::new(Atlas::new(facade, TEX_SIZE)?);