Add prof_leak_error option

The option makes the process to exit with error code 1 if a memory leak
is detected. This is useful for implementing automated tools that rely
on leak detection.

src/prof.c

@@ -31,6 +31,7 @@ ssize_t opt_lg_prof_interval = LG_PROF_INTERVAL_DEFAULT;
 bool opt_prof_gdump = false;
 bool opt_prof_final = false;
 bool opt_prof_leak = false;
+bool opt_prof_leak_error = false;
 bool opt_prof_accum = false;
 char opt_prof_prefix[PROF_DUMP_FILENAME_LEN];
 bool opt_prof_sys_thread_name = false;