Well, I'm one step further now, but not much.
Code:
linux:/home/gepard/Desktop/C Project # arm-linux-gcc -o area area.c circle.c
bash: arm-linux-gcc: command not found
ergo: something is still missing.
Code:
linux:/home/gepard/Desktop/gnuchess-5.07 # ./configure --host=arm-linux --prefix=/usr/local/arm/oe/arm-linux
bash: ./configure: Keine Berechtigung
yes, last line is in German, it means "no authorization" or so. Here is a problem again.

I set all rights [rwx] for user & group of the relevant directories.