Partial fix to VAR_EXTERN vs VAR_GLOBAL check. Now considers globals declared in resources too. TODO: recursively check FB declared in the program.

STD_TEST.st
STD_RESSOURCE.c
LOCATED_VARIABLES.h
POUS.c
test
STD_CONF.c
SFC_TEST.st
test.exe
plc.st
POUS.h
VARIABLES.csv