Hide/disable options when they're not available. Refs #788

* Hopefully these can be restored at some point, when the features are
  implemented. For now where possible we remove options that are just
  unavailable always, and selectively disable others when they may or
  may not be available based on what API the capture uses.

qrenderdoc/Windows/MainWindow.cpp

@@ -59,6 +59,12 @@ MainWindow::MainWindow(ICaptureContext &ctx) : QMainWindow(NULL), ui(new Ui::Mai
 {
   ui->setupUi(this);
 
+#if !defined(Q_OS_WIN32)
+  // process injection is not supported on non-Windows, so remove the menu item rather than disable
+  // it without a clear way to communicate that it is never supported
+  ui->menu_File->removeAction(ui->action_Inject_into_Process);
+#endif
+
   QToolTip::setPalette(palette());
 
   installEventFilter(this);