ld: signal_support.o:/..../minibash/src/./utils.h:18: multiple definition 
of `variableId'; minibash.o:/.../src/./utils.h:18: first defined here
ld: utils.o:/..../src/./utils.h:18: multiple definition of `variableId'; 
minibash.o:/..../src/./utils.h:18: first defined here
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:29: minibash] Error 1