Xcode 5.1.1 Release was released on 10 Apr 2014 and requires macOS 10.8+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/xcode_5.1.1/xcode_5.1.1.dmg.
Release notes are located at https://developer.apple.com/library/content/releasenotes/DeveloperTools/RN-Xcode/Chapters/Introduction.html#//apple_ref/doc/uid/TP40001051-CH1-SW504.
The compilers it contains are:
- clang 5.1 (Build 503.0.40)
- LLVM-GCC 3.4 (Build )