GL: add an ArrayView setTransformFeedbackOutputs() overload.

Interesting, I thought I have done this years ago already. Or that was
the multi-draw() maybe?

doc/changelog.dox

@@ -323,6 +323,9 @@ See also:
     prior to every draw, however with the new multidraw workflows that's no
     longer the case and the inability to chain draw calls proved to be
     annoying.
+-   Added an @ref GL::AbstractShaderProgram::setTransformFeedbackOutputs()
+    overload taking a @relativeref{Corrade,Containers::ArrayView} instead of
+    a @ref std::initializer_list
 -   The @ref GL::Context class got significantly optimized in terms of compile
     time, header size and runtime as well, significantly reducing the amount of
     allocations done at startup.

src/Magnum/GL/AbstractShaderProgram.cpp

@@ -548,8 +548,12 @@ void AbstractShaderProgram::bindFragmentDataLocationIndexedInternal(const Unsign
 #endif
 
 #ifndef MAGNUM_TARGET_GLES2
+void AbstractShaderProgram::setTransformFeedbackOutputs(const Containers::ArrayView<const std::string> outputs, const TransformFeedbackBufferMode bufferMode) {
+    (this->*Context::current().state().shaderProgram.transformFeedbackVaryingsImplementation)(outputs, bufferMode);
+}
+
 void AbstractShaderProgram::setTransformFeedbackOutputs(const std::initializer_list<std::string> outputs, const TransformFeedbackBufferMode bufferMode) {
-    (this->*Context::current().state().shaderProgram.transformFeedbackVaryingsImplementation)({outputs.begin(), outputs.size()}, bufferMode);
+    setTransformFeedbackOutputs(Containers::arrayView(outputs), bufferMode);
 }
 
 void AbstractShaderProgram::transformFeedbackVaryingsImplementationDefault(const Containers::ArrayView<const std::string> outputs, const TransformFeedbackBufferMode bufferMode) {

src/Magnum/GL/AbstractShaderProgram.h

@@ -1414,6 +1414,7 @@ class MAGNUM_GL_EXPORT AbstractShaderProgram: public AbstractObject {
          * @brief Specify shader outputs to be recorded in transform feedback
          * @param outputs       Names of output variables
          * @param bufferMode    Buffer mode
+         * @m_since_latest
          *
          * Binds given output variables from vertex, geometry or tessellation
          * shader to transform feedback buffer binding points. If
@@ -1440,7 +1441,8 @@ class MAGNUM_GL_EXPORT AbstractShaderProgram: public AbstractObject {
          * @requires_gl Special output names `gl_NextBuffer` and
          *      `gl_SkipComponents#` are not available in OpenGL ES or WebGL.
          */
-        void setTransformFeedbackOutputs(std::initializer_list<std::string> outputs, TransformFeedbackBufferMode bufferMode);
+        void setTransformFeedbackOutputs(Containers::ArrayView<const std::string> outputs, TransformFeedbackBufferMode bufferMode);
+        void setTransformFeedbackOutputs(std::initializer_list<std::string> outputs, TransformFeedbackBufferMode bufferMode); /**< @overload */
         #endif
 
         /**