How to make disk image with darktable application bundle (64 bit Intel only):

1). Install MacPorts (instructions and prerequisites can be found on official website), please use default installation path (/opt/local).
    They will need some tuning, so before you build anything add these lines to /opt/local/etc/macports/macports.conf:
     buildfromsource always
     macosx_deployment_target 10.14
    and this line to /opt/local/etc/macports/variants.conf:
     +no_gnome +no_x11 +quartz -x11 -gnome -gfortran
    Install required dependencies:
     $ sudo port install exiv2 libgphoto2 gtk-osx-application-gtk3 lensfun librsvg openexr json-glib GraphicsMagick openjpeg webp libsecret pugixml osm-gps-map adwaita-icon-theme tango-icon-theme intltool iso-codes libomp gmic-lib libheif portmidi libsdl2 libavif libjxl
    Clone darktable git repository (in this example into ~/src):
     $ mkdir ~/src
     $ cd ~/src
     $ git clone https://github.com/darktable-org/darktable.git
     $ cd darktable
     $ git submodule init
     $ git config submodule.src/tests/integration.update none
     $ git submodule update
    Finally build and install darktable:
     $ mkdir build
     $ cd build
     $ cmake .. -DCMAKE_OSX_DEPLOYMENT_TARGET=10.14 -DOpenMP_C_INCLUDE_DIR=/opt/local/include/libomp -DOpenMP_CXX_INCLUDE_DIR=/opt/local/include/libomp -DCMAKE_LIBRARY_PATH=/opt/local/lib/libomp -DBINARY_PACKAGE_BUILD=ON -DRAWSPEED_ENABLE_LTO=ON -DBUILD_CURVE_TOOLS=ON -DBUILD_NOISE_TOOLS=ON -DDONT_USE_INTERNAL_LUA=OFF
     $ make
     $ sudo cmake --install .
    After this darktable will be installed in /usr/local directory and can be started by typing the following command in terminal:
     $ GSETTINGS_SCHEMA_DIR=/opt/local/share/glib-2.0/schemas/ XDG_DATA_DIRS=/opt/local/share darktable

2). Download, patch and install gtk-mac-bundler (assuming darktable was cloned into ~/src directory):
     $ cd ~/src
     $ curl -LO https://download.gnome.org/sources/gtk-mac-bundler/0.7/gtk-mac-bundler-0.7.4.tar.xz
     $ tar -xf gtk-mac-bundler-0.7.4.tar.xz
     $ cd gtk-mac-bundler-0.7.4
     $ patch -p1 < ../darktable/packaging/macosx/gtk-mac-bundler-0.7.4.patch
     $ make install

3). Now preparation is done, run image creating script, it should create darktable-<VERSION>.dmg in current (packaging/macosx) directory:
     $ cd ~/src/darktable/packaging/macosx
     $ ./make-app-bundle
    If you have an Apple Developer ID Application certificate and want to produce signed app then replace the previous command with this one:
     $ CODECERT="Developer ID Application" APPLEID="developer@apple.id" APPLEPW="@keychain:DevIDPassword" ./make-app-bundle
    You may have to provide more specific name for a certificate if you have several matching in your keychain.

4). Assuming that darktable is the only program installed into /usr/local you should remove the install directory before doing next build:
     $ sudo rm -Rf /usr/local