I have compiled QGIS with Macports. 

qgis3 3.2.1 (source)
QGIS 3 is a user-friendly GIS based on Qt 5
Licenses: GPL-2+ 
Maintained by: vince atVeence openmaintainer
Categories: gis
Platforms: darwin 
Dependencies: cmake openssl qt5-qtbase bison expat fcgi gdal geos grass7 gsl ld64 libiconv libtasn1 libzip pkgconfig postgis2 postgresql10 proj py36-gdal py36-jinja2 py36-owslib py36-psycopg2 py36-pygments py36-pyqt5 py36-qscintilla-qt5 py36-requests py36-sip py36-six py36-yaml python36 qca-qt5 qca-qt5-ossl qjson-qt5 qt5-qtscript qt5-qtscxml qt5-qtwebkit qt5-qtxmlpatterns qt5-sqlite-plugin qtkeychain-qt5 qwt-qt5 spatialindex spatialite sqlite3 
Variants: debug grass postgresql10 postgresql95 postgresql96 proj4 proj5 python34 python35 python36


The problem has been solved.

Regards

Ivano

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/hbKGW.png