Bulk build on macOS 10.13 High Sierra fails (gdb can't be build)

Hey all,

I'm trying to do a bulk build of all toolchains with the build-all 
target on a macOS 10.13 High Sierra box.

WHAT WORKS

I know this infos: 
http://crosstool-ng.org/hg/crosstool-ng/file/715b711da3ab/docs/MacOS-X.txt

The base environment works fine. So crosstool-NG is compiled and able to 
do things.

WHAT I WANT TO DO

As a command this:

./ct-ng build-all.8 CT_PREFIX=/Volumes/Crosstool/

Simply a bulk build of all samples. A few will fail I think but the most 
work on Debian Stretch 9.

SYSTEM INFOS

The system is a macOS 10.13 High Sierra. The package manager is 
Homebrew. The info about the installed packages is in the tar.bz2 file 
linked blow as .txt files.

WHAT FAILS

The build of toolchains which build on e.g. Debian 9 Stretch. The logs 
are in the tar.bz2 file linked below. If I'm right it fails in the 
compilation of GDB because there are problems compiling against the 
C/C++ libraries/frameworks shipped with XCode.

Link to tar.bz2: http://www12.zippyshare.com/v/hQOezvuY/file.html

Does someone has a solution for this problem?

Best Regards