Fixed bug where OpenBSD couldn't compile

CMakeLists.txt

 project( "slop" )
 set( slop_VERSION_MAJOR 4 )
 set( slop_VERSION_MINOR 2 )
-set( slop_VERSION_PATCH 16 )
+set( slop_VERSION_PATCH 17 )
 
 set( CMAKE_OPENGL_SUPPORT FALSE CACHE BOOL "Whether or not to compile with OpenGL, shaders, magnification, and theming support." )
 

README.md

 help
 ----
 ```text
-slop v4.2.16
+slop v4.2.17
 
 Copyright (C) 2014 Dalton Nell, Slop Contributors
 (https://github.com/naelstrof/slop/graphs/contributors)
     $ # Classic Windows XP selection.
     $ slop -l -c 0.3,0.4,0.6,0.4
 
+    $ # Wiggle wiggle!
+    $ slop --opengl --shader wiggle
+
+    $ # Edgy textures or something.
+    $ slop --opengl --theme gothic
+
     $ # Change output format to use safer parsing
     $ slopoutput=$(slop -f "%x %y %w %h")
     $ X=$(echo $slopoutput | awk '{print $1}')

src/framebuffer.hpp

 #include <GL/glew.h>
 #include <GL/gl.h>
 #include <glm/glm.hpp>
+#include <stdexcept>
 
 #include "x.hpp"
 #include "shader.hpp"