Solution Configuration but not Platform in VS2010 Toolbar

I had the same issue, here is how I got the menu back

1. On the menubar go to View → Toolbars → Customize...
2. Click on the "Commands" tab
3. Select the "Toolbar" radio button and find "Standard" in the drop down list
4. Click the "Add Command..." button
5. Select the "Build" category
6. Find and select the "Solution Platforms" command and click "OK"
7. Move your new command to a comfortable place on your toolbar using "Move Up" and "Move Down"
8. Enjoy not having to dig through Solution Properties to change the platform

in my case the toolbar was not showing. the above answer helped me find a simpler solution

VIEW > Toolbars > ✓ Standard