If there are not externs on these forward declarations, it's entirely possible for the program to link and missing data to be assigned to someplace presumed in IWRAM or something.
Command used for the job:
egrep -rl ' $' --include *.c --include *.h --include *.s --include *.inc --include *.txt * | xargs sed -i 's/\s\+$//g'
Credits to Grant Murphy from Stack Overflow.
