GL_EXT_histogram
http://oss.sgi.com/projects/ogl-sample/registry/EXT/histogram.txt
	GL_HISTOGRAM_EXT 0x8024
	GL_PROXY_HISTOGRAM_EXT 0x8025
	GL_HISTOGRAM_WIDTH_EXT 0x8026
	GL_HISTOGRAM_FORMAT_EXT 0x8027
	GL_HISTOGRAM_RED_SIZE_EXT 0x8028
	GL_HISTOGRAM_GREEN_SIZE_EXT 0x8029
	GL_HISTOGRAM_BLUE_SIZE_EXT 0x802A
	GL_HISTOGRAM_ALPHA_SIZE_EXT 0x802B
	GL_HISTOGRAM_LUMINANCE_SIZE_EXT 0x802C
	GL_HISTOGRAM_SINK_EXT 0x802D
	GL_MINMAX_EXT 0x802E
	GL_MINMAX_FORMAT_EXT 0x802F
	GL_MINMAX_SINK_EXT 0x8030
	void glGetHistogramEXT (GLenum target, GLboolean reset, GLenum format, GLenum type, void* values)
	void glGetHistogramParameterfvEXT (GLenum target, GLenum pname, GLfloat* params)
	void glGetHistogramParameterivEXT (GLenum target, GLenum pname, GLint* params)
	void glGetMinmaxEXT (GLenum target, GLboolean reset, GLenum format, GLenum type, void* values)
	void glGetMinmaxParameterfvEXT (GLenum target, GLenum pname, GLfloat* params)
	void glGetMinmaxParameterivEXT (GLenum target, GLenum pname, GLint* params)
	void glHistogramEXT (GLenum target, GLsizei width, GLenum internalformat, GLboolean sink)
	void glMinmaxEXT (GLenum target, GLenum internalformat, GLboolean sink)
	void glResetHistogramEXT (GLenum target)
	void glResetMinmaxEXT (GLenum target)