From @cpansprout

This used to work, until $$ was made magical and autovivificable​:

  int _pid_ = SvIV(get_sv("$", FALSE));

With some symbol table entries, perl does not bother creating them on startup, but only when they are first accessed. But when they are accessed, it pretends that they had been there all along.

Passing ADDMG to gv_fetchpvn_flags means that lookup will autovivify such typeglobs.

Should get_sv be doing that? Currently it is not.

Flags​:
  category=core
  severity=low

Site configuration information for perl 5.17.6​:

Configured by sprout at Sat Nov 17 23​:09​:15 PST 2012.

Summary of my perl5 (revision 5 version 17 subversion 6) configuration​:
  Local Commit​: e1d8196c98d7cc6d34eedc83ba4193885673d43d
  Ancestor​: 10ffaf9
  Platform​:
  osname=darwin, osvers=10.5.0, archname=darwin-thread-multi-2level
  uname='darwin pint.local 10.5.0 darwin kernel version 10.5.0​: fri nov 5 23​:20​:39 pdt 2010; root​:xnu-1504.9.17~1release_i386 i386 '
  config_args='-de -DDEBUGGING -Duseithreads -Dusedevel -Accflags= -fcatch-undefined-behavior -DPERL_POISON'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=define, usemultiplicity=define
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=undef, use64bitall=undef, uselongdouble=undef
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='gcc', ccflags ='-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
  optimize='-O3 -g',
  cppflags='-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
  ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
  intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
  ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
  alignbytes=8, prototype=define
  Linker and Libraries​:
  ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib
  libs=-ldbm -ldl -lm -lutil -lc
  perllibs=-ldl -lm -lutil -lc
  libc=, so=dylib, useshrplib=false, libperl=libperl.a
  gnulibc_version=''
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
  cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector'

Locally applied patches​:
 

@​INC for perl 5.17.6​:
  /usr/local/lib/perl5/site_perl/5.17.6/darwin-thread-multi-2level
  /usr/local/lib/perl5/site_perl/5.17.6
  /usr/local/lib/perl5/5.17.6/darwin-thread-multi-2level
  /usr/local/lib/perl5/5.17.6
  /usr/local/lib/perl5/site_perl
  .

Environment for perl 5.17.6​:
  DYLD_LIBRARY_PATH (unset)
  HOME=/Users/sprout
  LANG=en_US.UTF-8
  LANGUAGE (unset)
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/usr/bin​:/bin​:/usr/sbin​:/sbin​:/usr/local/bin​:/usr/X11/bin​:/usr/local/bin
  PERL_BADLANG (unset)
  SHELL=/bin/bash