

At least that worked for me, may not for others. Then all 13 packages and freeswitch installed fine. For curiosity, I installed HB on a clean system, deleted /library/developer CLT installed HB, ran Xcode-select to point to Xcode CLT. Interesting observation: I did a lot of research and the only difference I found is Metal which is in the Xcode CLT and not in the standalone CLT, there may be other differences but I could not find them.

Since it is not a package formula that triggers this, I realize it's the Homebrew ruby installation formula that triggers standalone CLT installation. I was confused since I thought your comment meant a "package formula" triggered the standalone CLT, but no packages were referenced prior to CLT installation. On a clean system a fresh install of HB using the ruby install command causes the standalone CLT to be installed, before any packages are installed. Thanks for your quick responses, I really appreciate it.

To get around two CLTs I installed HB on another system then copying /usr/local. HB installs a second copy of CLT if you have Xcode. I tested with only Xcode installed and everything worked fine. This is a change to HB since it used to use Xcode CLT if found. If HB is installed from scratch into an empty /usr/local it forces CLT download into /library/developer even if CLT is already in XCODE. I ran brew doctor without /library/developer CLT and it said ready/good.

In other words, if HB is already in /usr/local and never installed the CLT, but XCODE is installed, HB does NOT download CLT into /library/developer, it's happy with the existing Xcode CLT. This test shows that CLT is installed with XCODE with no need for a separate CLT. If I install 10.13 or 10.14 from scratch, then install XCODE, then copy /usr/local from a system with HB already on: all 13 packages install fine and freeswitch compiles perfectly even without a separate CLT not installed into /library/developer. This seems like bug and is not unique to Mojave/Xcode 10 since it also occurs on 10.13/Xcode 9.4.1.
