title: Swift build settings in Xcode to use lower 4.0.3 version instead of 5.0.1 are not enforced
body: <p>I'm creating a simple Swift framework in <code>Xcode 10.3</code> and trying to use a lower <code>Swift 4.0.3</code> version. I went to the Xcode build settings and switch from 5.0.1 to 4.0.3 and then build the project.</p>
  
  <p><a href="https://i.stack.imgur.com/eVonj.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/eVonj.jpg" alt="enter image description here"></a></p>
  
  <p>I ran <code>otool</code> against resulted framework to make sure it's built using correct Swift version but the libraries included are still from Swift 5.0.1 (corresponds to 1001.0.82 from the output below):</p>
  
  <blockquote>
    <p>otool -l SwiftyHello.framework/SwiftyHello</p>
  </blockquote>
  
  <pre><code>cmd LC_LOAD_DYLIB
  cmdsize 56
  name @rpath/libswiftCore.dylib (offset 24)
  time stamp 2 Wed Dec 31 16:00:02 1969
  current version **1001.0.82**
  compatibility version 1.0.0
  </code></pre>
  
  <p>My toolchain is running Swift 5.0.1:</p>
  
  <blockquote>
    <p>swift -version</p>
  </blockquote>
  
  <pre><code>Apple Swift version 5.0.1 (swiftlang-1001.0.82.4 clang-1001.0.46.5)
  Target: x86_64-apple-darwin18.7.0
  </code></pre>
  
  <p>How can I make sure that the Swift framework is built using Swift 4.0.3?</p>