Platform: remove full value specification from Flags EnumSets.

I don't see any use case for just specifying "all the flags", mainly
because the flags are mutually conflicting and whatnot. Also, these go
outdated *fast*.

src/Magnum/Platform/Sdl2Application.h

@@ -1269,17 +1269,8 @@ class Sdl2Application::GLConfiguration {
          * @see @ref setFlags(), @ref GL::Context::Flags
          * @requires_gles Context flags are not available in WebGL.
          */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        typedef Containers::EnumSet<Flag, SDL_GL_CONTEXT_DEBUG_FLAG|
-            SDL_GL_CONTEXT_ROBUST_ACCESS_FLAG|SDL_GL_CONTEXT_RESET_ISOLATION_FLAG
-            #ifndef MAGNUM_TARGET_GLES
-            |SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG
-            #endif
-            > Flags;
-        #else
         typedef Containers::EnumSet<Flag> Flags;
         #endif
-        #endif
 
         explicit GLConfiguration();
         ~GLConfiguration();

src/Magnum/Platform/WindowlessEglApplication.h

@@ -213,16 +213,8 @@ class WindowlessEglContext::Configuration {
          * @see @ref setFlags(), @ref Context::Flags
          * @requires_gles Context flags are not available in WebGL.
          */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        typedef Containers::EnumSet<Flag, EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR
-            #ifndef MAGNUM_TARGET_GLES
-            |EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR
-            #endif
-            > Flags;
-        #else
         typedef Containers::EnumSet<Flag> Flags;
         #endif
-        #endif
 
         /*implicit*/ Configuration();
 

src/Magnum/Platform/WindowlessGlxApplication.h

@@ -216,15 +216,7 @@ class WindowlessGlxContext::Configuration {
          *
          * @see @ref setFlags(), @ref Context::Flags
          */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        typedef Containers::EnumSet<Flag, GLX_CONTEXT_DEBUG_BIT_ARB
-            #ifndef MAGNUM_TARGET_GLES
-            |GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB
-            #endif
-            > Flags;
-        #else
         typedef Containers::EnumSet<Flag> Flags;
-        #endif
 
         /*implicit*/ Configuration();
 

src/Magnum/Platform/WindowlessWglApplication.h

@@ -203,15 +203,7 @@ class WindowlessWglContext::Configuration {
          *
          * @see @ref setFlags(), @ref Context::Flags
          */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        typedef Containers::EnumSet<Flag, WGL_CONTEXT_DEBUG_BIT_ARB
-            #ifndef MAGNUM_TARGET_GLES
-            |WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB
-            #endif
-            > Flags;
-        #else
         typedef Containers::EnumSet<Flag> Flags;
-        #endif
 
         /*implicit*/ Configuration();
 

src/Magnum/Platform/WindowlessWindowsEglApplication.h

@@ -179,11 +179,7 @@ class WindowlessWindowsEglContext::Configuration {
          *
          * @see @ref setFlags(), @ref Context::Flags
          */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        typedef Containers::EnumSet<Flag, EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR> Flags;
-        #else
         typedef Containers::EnumSet<Flag> Flags;
-        #endif
 
         constexpr /*implicit*/ Configuration() {}