Cmake errors installing on mac os 10.13.1

[rful011]

I have had several goes at running brew install --no-sandbox qgis/qgisdev/qgis3-dev. First try gave an error for giflib because its components were already installed in /usr/local/bin. The install continued and terminated without any other errors until it had installed gdal. It did not download and install QGIS.

I ran the install again and it updated brew (probably not relevant) and then installed python-gdal and started on QGIS itself but died during make:

`==> Checking out branch master
==> /usr/local/bin/pip3 install --user future psycopg2 python-dateutil httplib2 pytz six nose2 pygments jinja2 pyyaml requ
==> cmake -G Ninja -DCMAKE_C_FLAGS_RELEASE=-DNDEBUG -DCMAKE_CXX_FLAGS_RELEASE=-DNDEBUG -DCMAKE_INSTALL_PREFIX=/usr/local/C
Last 15 lines from /Users/rful011/Library/Logs/Homebrew/qgis3-dev/02.cmake:
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
used as include directory in directory /tmp/qgis3-dev-20171212-26875-96y6za/python
QTKEYCHAIN_LIBRARY
linked by target "qgis_core" in directory /tmp/qgis3-dev-20171212-26875-96y6za/src/core

-- Configuring incomplete, errors occurred!
See also "/tmp/qgis3-dev-20171212-26875-96y6za/build/CMakeFiles/CMakeOutput.log".
.....
macMini:QGIS3.0 rful011$ less /tmp/qgis3-dev-20171212-26875-96y6za/build/CMakeFiles/CMakeOutput.log
/tmp/qgis3-dev-20171212-26875-96y6za/build/CMakeFiles/CMakeOutput.log: No such file or directory
`
It looks like brew helpfully removes the build directory :(

Is this related to the python 3.6 issue or something else?