gnuc platforms, but not needed there. This uses GCC
to silence GCC specific warnings by marking pTHX as
unused.
p4raw-id: //depot/perl@11997
#ifdef PERL_IMPLICIT_CONTEXT
# ifdef USE_5005THREADS
struct perl_thread;
-# define pTHX register struct perl_thread *thr
+# define pTHX register struct perl_thread *thr PERL_UNUSED_DECL
# define aTHX thr
# define dTHR dNOOP /* only backward compatibility */
# define dTHXa(a) pTHX = (struct perl_thread*)a
# ifndef MULTIPLICITY
# define MULTIPLICITY
# endif
-# define pTHX register PerlInterpreter *my_perl
+# define pTHX register PerlInterpreter *my_perl PERL_UNUSED_DECL
# define aTHX my_perl
# define dTHXa(a) pTHX = (PerlInterpreter*)a
# endif