[BRLTTY] Errors in building revision 4534 from SVN

[Hermann]

Hi,
while building revision 4534 from the SVN repo, I get the following errors 
when performing make:

make[3]: *** No rule to make target `host_keycodes.o'.  Stop.
make[2]: *** [../../../Programs/host_keycodes.o] Error 2
make[1]: *** [braille-drivers] Error 1
make: *** [all] Error 2

What has caused this?
Hermann