title: Unable to compile and run simple Ada application
body: <p>Very new to Ada and have started to learn by doing a Hello World tutorial in GNAT GPS. I'm having a hard time figuring out an error when I compile my code. The error looks like a source file dir issue. But I'm highly unfamiliar with the error output in this type of IDE.</p>
  
  <p>Here is the code I'm trying to compile and run (file: main.adb):</p>
  
  <pre><code>with Ada.Text_IO;
  
  procedure Main is
  
  begin
     Ada.text_IO.Put_Line("Hello world!");
     null;
  end Main;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/umtqE.png" rel="nofollow noreferrer">Image of code and GPS IDE</a></p>
  
  <p>Here's the build error I'm receiving:</p>
  
  <pre><code>gprbuild -d -P/Users/myname/Desktop/Test/default.gpr /Users/myname/Desktop/Test/src/main.adb
  Compile
     [Ada]          main.adb
  Bind
     [gprbind]      main.bexch
     [Ada]          main.ali
  Link
     [link]         main.adb
  ld: library not found for -lSystem
  collect2: error: ld returned 1 exit status
  gprbuild: link of main.adb failed
  gprbuild: failed command was: /users/myname/opt/gnat/2019/bin/gcc main.o b__main.o -L/Users/myname/Desktop/Test/obj/ -L/Users/myname/Desktop/Test/obj/ -L/users/myname/opt/gnat/2019/lib/gcc/x86_64-apple-darwin17.7.0/8.3.1/adalib/ /users/myname/opt/gnat/2019/lib/gcc/x86_64-apple-darwin17.7.0/8.3.1/adalib/libgnat.a -Wl,-rpath,@executable_path/ -Wl,-rpath,@executable_path/../../..//opt/gnat/2019/lib/gcc/x86_64-apple-darwin17.7.0/8.3.1/adalib -o main
  [2019-10-19 11:34:54] process exited with status 4, elapsed time: 01.95s
  </code></pre>
  
  <p>I'm assuming I installed Ada incorrectly and or GPS. Any suggestions or thoughts? Thank you.</p>
  
  <p><strong>Update/Additional thoughts:</strong></p>
  
  <p>One other thing I'm assuming is that the project is unable to find the Ada source code since the project is saved on the /desktop?</p>