+ In the child process, it just "return"s so that the calling code is
+ actually run under "valgrind".
+
+VARIABLES
+ $dl_unload
+ When set to true, all dynamic extensions that were loaded during the
+ analysis will be unloaded at "END" time by DynaLoader::dl_unload_file.
+
+ Since this obfuscates error stack traces, it's disabled by default.
+
+CAVEATS