Fix compilation on not-exactly-recent updates of MSVC 2015.

src/Magnum/Context.cpp

@@ -694,7 +694,7 @@ bool Context::tryCreate() {
     if(!_driverWorkarounds.empty()) {
         Debug{output} << "Using driver workarounds:";
         for(const auto& workaround: _driverWorkarounds)
-            if(!workaround.second) Debug{output} << "   " << workaround.first;
+            if(!workaround.second) Debug(output) << "   " << workaround.first;
     }
 
     /* Initialize functionality based on current OpenGL version and extensions */

src/Magnum/Implementation/State.cpp

@@ -81,7 +81,7 @@ State::State(Context& context, std::ostream* const out) {
     extensions.erase(std::unique(extensions.begin(), extensions.end()), extensions.end());
 
     Debug{out} << "Using optional features:";
-    for(const auto& ext: extensions) Debug{out} << "   " << ext;
+    for(const auto& ext: extensions) Debug(out) << "   " << ext;
 }
 
 State::~State() = default;