Platform: properly initialize EmscriptenApp GLConfiguration.

doc/changelog.dox

@@ -89,6 +89,9 @@ See also:
 
 @subsection changelog-latest-bugfixes Bug fixes
 
+-   @ref Platform::EmscriptenApplication randomly created antialiased contexts
+    due to an uninitialized variable in its
+    @ref Platform::EmscriptenApplication::GLConfiguration "GLConfiguration"
 -   Creating @ref Platform::WindowlessEglApplication again after it was
     destroyed could fail with an error saying "cannot make the previous context
     current" on certain system. This was due to EGL not destroying the context

src/Magnum/Platform/EmscriptenApplication.cpp

@@ -692,7 +692,8 @@ void EmscriptenApplication::textInputEvent(TextInputEvent&) {}
 
 #ifdef MAGNUM_TARGET_GL
 EmscriptenApplication::GLConfiguration::GLConfiguration():
-    _colorBufferSize{8, 8, 8, 8}, _depthBufferSize{24}, _stencilBufferSize{0} {}
+    _colorBufferSize{8, 8, 8, 8}, _depthBufferSize{24}, _stencilBufferSize{0},
+    _sampleCount{0} {}
 #endif
 
 int EmscriptenApplication::exec() {