adapt child handling to nawk from *BSD

Author: hexcoder-

afl-cmin

@@ -403,13 +403,13 @@ BEGIN {
     retval = system( "AFL_CMIN_ALLOW_ANY=1 \""showmap"\" -m "mem_limit" -t "timeout" -o \""trace_dir"\" -Z "extra_par" -i \""in_dir"\" -- \""target_bin"\" "prog_args_string" </dev/null")
   }
 
-  if (retval > 127) {
-    retval = retval - 128
-    if (retval > 127) {
-      retval = retval - 128
+  if (retval) {
+    print "[!]Exit code != 0 received from afl-showmap, terminating..."
+
+    if (!ENVIRON["AFL_KEEP_TRACES"]) {
+      system("rm -rf "trace_dir" 2>/dev/null")
     }
-    printf "[!]Signal %d received, terminating...\n", retval
-    exit 1
+    exit retval
   }
 
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