Add a simple stack_walker test

tests/Makefile

@@ -0,0 +1,8 @@
+CXX=g++
+CXXFLAGS=-Wall -Wextra -O2 -g -I../stack_walker -rdynamic
+
+stack_walked.bin: stack_walked.cpp
+	$(CXX) $(CXXFLAGS) -o $@ $^ -L../stack_walker -ldl -lstack_walker
+
+clean:
+	rm *.bin

tests/stack_walked.cpp

@@ -0,0 +1,15 @@
+#include <cstdio>
+#include <dlfcn.h>
+
+#include "../stack_walker/stack_walker.hpp"
+
+int main() {
+    Dl_info main_info;
+    int rc = dladdr((void*)&main, &main_info);
+
+    printf("I'm in %s!\n", (rc != 0) ? main_info.dli_sname : "[No data]");
+
+    stack_walker_init();
+
+    return 0;
+}