/usr/local/bin/arm-elf-eabi-cpp
And of course /usr/local/bin/ is in my $PATH.
Where is cc1 supposed te be after the installation?
EDIT
Ok, it looks like the good old permission issue. rockboxdev.sh puts everithing into /usr/local/libexec, but
drwxr-s--- 3 root staff 4,0K lug 23 22:18 libexec/
normal users cannot enter that directory and the others nested.
I don't know how rockboxdev.sh manages premissions, but I suspect that some other script has messed with that directory.