🚀 go-pugleaf

I have a problem with extern variables. If in module A the varaiable var,
which is declarated in a module b, is declarated as "extern var", the linker
produces an output like: undefined symbol _var is ref.. from text.

Here an extract of my MAKEFILE:

CFLAGS=-O -fomit-frame-pointer -fcombine-regs -fstrength-reduce
CC=e:\gnu\usr\gnu\bin\gcc.ttp $(CFLAGS)
LINK=e:\gnu\usr\gnu\bin\gcc-ld.ttp

anruftod.app:   main.o einstell.o bedienfe.o mitteilu.o tcframe.o
    $(LINK) -oanruftod.app e:\gnu\usr\gnu\lib\crt0.o @files.lst -lgnu -lgem
-liio

What is the reason? Is there any compiler or linker option to eleminate the
problem?

I'm using GCC 2.1 on an ATARI ST.

Greetings
 Axel