Example for failing compile on system symbol usage

fncheck.c

void not_thread_safe();

void puts() { not_thread_safe(); }

Makefile

all: should_work.x should_fail.x

should_fail.x : should_fail.o fncheck.o
	gcc should_fail.o fncheck.o -Xlinker -dead_strip -o should_fail.x

should_work.x : should_work.o fncheck.o
	gcc should_work.o fncheck.o -Xlinker -dead_strip -o should_work.x

should_fail.o : should_fail.c
	gcc -c should_fail.c

should_work.o : should_work.c
	gcc -c should_work.c

fncheck.o : fncheck.c
	gcc -c fncheck.c

should_fail.c

#include <stdio.h>

int main (int argc, char *argv[]) {
    printf ("Hello, world.\n");
    return 0;
}

should_work.c

#include <stdio.h>

int main (int argc, char *argv[]) {
    return 0;
}