@mfalkvidd thanks for your help. Unfortunately, this didn't resolve the issue. I repeated the installation, this time deliberately executing sudo make install, but the problem remained.
@hayduke Maybe this indeed is an issue with Raspbian Jessie as I am on Jessie.

Hi there
I did everything according to the instructions. Installing went without complications. However, when trying to verify the gateway problems arise.

After typing

sudo /usr/local/sbin/PiGatewaySerial

I receive the message: command not found.
Also, no /dev/ttyMySensorsGateway file has been created.

When I am entering

sudo /etc/init.d/PiGatewaySerial start

nothing happens. I only get a new command line.

I can start the gateway, however, when I am entering

sudo ./PiGatewaySerial

in the Raspberry folder.

I already tried to uninstall and re-install everything, without success. Has anybody any suggestions how to solve this issue?