CMake server fails to start with non-existing pipe-path

Summary

I was trying to open a number of projects in the new Qt Creator 4.7.0 on my MacBookPro. Every time I encountered a problem with the CMake server opening a socket. I went on and investigated the issue as far as I could. I was getting the following error message:

{{ Running "/Applications/CMake.app/Contents/bin/cmake -E server --pipe=/tmp/cmake.wOLGoa/socket --experimental" in /Some/Build/Directory.}}
{{ Parsing of CMake project failed: Connection to CMake server lost.}}

I then ran the exact command in my shell, and got the following message:
CMake Error: Internal Error with /Users/gyula.gubacsi/cmake/socket: EACCES

EACCESS, looking through the source code, is coming from libuv. Further inspection, I found that libuv report EACCESS even if the socket creation failed with ENOENT. Also I tried with sudo permission, just for the sake of it, but no joy.
However, ENOENT was a clue, so I tried to pre-create the directory and the command started up the server without any issues.

Now, I know that the code is working on Linux at least. I looked at the source code of Qt Creator and found that the pipe should be created in a temporary directory, that is supposed to be created in the constructor call. So at this point this might be a Qt 5.11 related bug, but I couldn't track any further.

Reproduction

1. On a MacOS system
2. Open Qt Creator 4.7.0 release
3. Open any CMakeLists.txt project

Expected result

The project opens as normal: import dialog if it wasn't configured properly before. Otherwise opens the project straight away.

Actual result

The project is not opened and the General messages tab shows the following error:
Running "/Applications/CMake.app/Contents/bin/cmake -E server --pipe=/tmp/cmake.wOLGoa/socket --experimental" in /Some/Build/Directory.
{{ Parsing of CMake project failed: Connection to CMake server lost.}}