Added EXT_shader_texture_lod ES2 extension.

doc/opengl-support.dox

@@ -250,6 +250,7 @@ supported.
 @es_extension{EXT,texture_type_2_10_10_10_REV} | done
 @es_extension{EXT,discard_framebuffer}       | done
 @es_extension2{EXT,blend_minmax,blend_minmax} | done
+@es_extension{EXT,shader_texture_lod}        | done (shading language only)
 @es_extension{EXT,occlusion_query_boolean}   | done
 @es_extension{EXT,texture_rg}                | done
 @es_extension{EXT,texture_storage}           | done

src/Magnum/Context.cpp

@@ -219,6 +219,7 @@ const std::vector<Extension>& Extension::extensions(Version version) {
         _extension(GL,EXT,texture_type_2_10_10_10_REV),
         _extension(GL,EXT,discard_framebuffer),
         _extension(GL,EXT,blend_minmax),
+        _extension(GL,EXT,shader_texture_lod),
         _extension(GL,EXT,occlusion_query_boolean),
         _extension(GL,EXT,texture_rg),
         _extension(GL,EXT,texture_storage),

src/Magnum/Extensions.h

@@ -232,6 +232,9 @@ namespace GL {
         _extension(GL,EXT,blend_minmax,             GLES200, GLES300) // #65
         #endif
         _extension(GL,EXT,read_format_bgra,         GLES200,    None) // #66
+        #ifdef MAGNUM_TARGET_GLES2
+        _extension(GL,EXT,shader_texture_lod,       GLES200, GLES300) // #77
+        #endif
         _extension(GL,EXT,debug_label,              GLES200,    None) // #98
         _extension(GL,EXT,debug_marker,             GLES200,    None) // #99
         #ifdef MAGNUM_TARGET_GLES2