Starting with a fresh BUILDROOT, sh osxbuild.sh builddeps fails. Here's the CMakeOutput from BUILDROOT/depbuild/CMakeFiles after running the builddeps command.

The error not in your log probably has to do with ext_qt not finding zlib. the problem with the osxbuild of this git moment was that it stopped on any build error.

If it is indeed the ext_qt package that failed (I suspect it since I just discovered this one was causing problems on fresh builds). build first ext_zlib and ext_extra_cmake_modules before ext_qt

with the latest osxbuild.sh from master:

./osxbuild.sh builddeps ext_zlib ext_extra_cmake_modules
./osxbuild.sh builddeps

Now it should finish building all. The reason for the error was some changes cmake process due to update Qt version 5.12.2

This patch in question only alters the creation of the dmg but not the build process.