kyrios Thank you for your answer. This weird installation path is common in the ROCm library stack and people are complaining about this. But I'll try how far I will come with the locations you suggest. I changed now the package.yml file according to your suggestions:
install -D -m 00644 libhsakmt.so.1.0.0 $installdir/%libdir%/rocm/libhsakmt.so.1.0.0
ln -s $installdir/%libdir%/libhsakmt.so.1.0.0 $installdir/%libdir%/rocm/libhsakmt.so.1
ln -s $installdir/%libdir%/libhsakmt.so.1.0.0 $installdir/%libdir%/rocm/libhsakmt.so
cd ..
install -Dm00644 include/hsakmt.h $installdir/usr/include/rocm/hsakmt.h
install -Dm00644 include/hsakmttypes.h $installdir/usr/include/rocm/hsakmttypes.h
install -Dm00644 include/linux/kfd_ioctl.h $installdir/usr/include/rocm/linux/kfd_ioctl.h
Now I also get a *.eopkg file containing the libraries and a devel.eopkg file containing the headers. I will try if I can proceed with this.