Added FindOpenGLES3.cmake module.

Seems that Mesa has both ES2 and ES3 in the same libGLESv2.so. Weird.

CMakeLists.txt

@@ -76,8 +76,10 @@ endif()
 find_package(Corrade REQUIRED)
 if(NOT TARGET_GLES OR TARGET_DESKTOP_GLES)
     find_package(OpenGL REQUIRED)
-else()
+elseif(TARGET_GLES2)
     find_package(OpenGLES2 REQUIRED)
+else()
+    find_package(OpenGLES3 REQUIRED)
 endif()
 if(NOT TARGET_GLES)
     find_package(GLEW REQUIRED)

modules/FindOpenGLES3.cmake

@@ -0,0 +1,48 @@
+# - Find OpenGL ES 3
+#
+# This module defines:
+#
+#  OPENGLES3_FOUND          - True if OpenGL ES 3 library is found
+#  OPENGLES3_LIBRARY        - OpenGL ES 3 library
+#  OPENGLES3_INCLUDE_DIR    - Include dir
+#
+
+#
+#   This file is part of Magnum.
+#
+#   Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>
+#
+#   Permission is hereby granted, free of charge, to any person obtaining a
+#   copy of this software and associated documentation files (the "Software"),
+#   to deal in the Software without restriction, including without limitation
+#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
+#   and/or sell copies of the Software, and to permit persons to whom the
+#   Software is furnished to do so, subject to the following conditions:
+#
+#   The above copyright notice and this permission notice shall be included
+#   in all copies or substantial portions of the Software.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#   DEALINGS IN THE SOFTWARE.
+#
+
+# Library
+find_library(OPENGLES3_LIBRARY NAMES
+    GLESv2) # wtf?
+
+# Include dir
+find_path(OPENGLES3_INCLUDE_DIR
+    NAMES gl3.h
+    PATH_SUFFIXES GLES3
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args("OpenGLES3" DEFAULT_MSG
+    OPENGLES3_LIBRARY
+    OPENGLES3_INCLUDE_DIR
+)

src/CMakeLists.txt

@@ -158,8 +158,10 @@ set(Magnum_LIBS
     ${CORRADE_PLUGINMANAGER_LIBRARY})
 if(NOT TARGET_GLES OR TARGET_DESKTOP_GLES)
     set(Magnum_LIBS ${Magnum_LIBS} ${OPENGL_gl_LIBRARY})
-else()
+elseif(TARGET_GLES2)
     set(Magnum_LIBS ${Magnum_LIBS} ${OPENGLES2_LIBRARY})
+else()
+    set(Magnum_LIBS ${Magnum_LIBS} ${OPENGLES3_LIBRARY})
 endif()
 if(NOT TARGET_GLES)
     set(Magnum_LIBS ${Magnum_LIBS} ${GLEW_LIBRARIES})