Fix internal framebuffer binding on WebGL.

For some weird reason this was failing only on the Viewer example and
not anywhere else. Huh.

src/Magnum/AbstractFramebuffer.cpp

@@ -105,10 +105,10 @@ void AbstractFramebuffer::bind() {
 }
 
 void AbstractFramebuffer::bindInternal(FramebufferTarget target) {
-    #ifndef MAGNUM_TARGET_GLES2
-    bindImplementationDefault(target);
-    #else
+    #if defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
     (this->*Context::current()->state().framebuffer->bindImplementation)(target);
+    #else
+    bindImplementationDefault(target);
     #endif
 }
 
@@ -146,10 +146,10 @@ void AbstractFramebuffer::bindImplementationDefault(FramebufferTarget target) {
 }
 
 FramebufferTarget AbstractFramebuffer::bindInternal() {
-    #ifndef MAGNUM_TARGET_GLES2
-    return bindImplementationDefault();
-    #else
+    #if defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
     return (this->*Context::current()->state().framebuffer->bindInternalImplementation)();
+    #else
+    return bindImplementationDefault();
     #endif
 }
 

src/Magnum/Implementation/FramebufferState.h

@@ -54,7 +54,7 @@ struct FramebufferState {
     #ifndef MAGNUM_TARGET_GLES2
     void(AbstractFramebuffer::*invalidateSubImplementation)(GLsizei, const GLenum*, const Range2Di&);
     #endif
-    #ifdef MAGNUM_TARGET_GLES2
+    #if defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
     void(AbstractFramebuffer::*bindImplementation)(FramebufferTarget);
     FramebufferTarget(AbstractFramebuffer::*bindInternalImplementation)();
     #endif