Fix segfault if no instances of a section are in the final result If no instances of a section are found to be included in the final linked binary, print a warning instead of crashing with a segfault.

\.exe$
\.o$
\.d$
\.a$
~$
\.orig$
/lwbasic$
/lwlink$
/lwobjdump$
/lwar$
/lwasm$
/lwcc/lwcc$
/lwcc/lwcc-cpp$
/lwcc/lwcc-cc

# for windows
\.suo$
\.sdf$
\.opensdf$
\Debug$
\Release$