[pmc2c] There's a signal handler in pmc2c which upgrades warnings to …

…errors (with a Carp backtrace).

This looks like a useful debugging tool, but when combined with the deprecation warning I introduced
in r38932, it causes test failures.  Add a comment and disable it for now.

git-svn-id: https://svn.parrot.org/parrot/trunk@38940 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

lib/Parrot/Pmc2c/Pmc2cMain.pm

@@ -24,7 +24,8 @@ use Parrot::Pmc2c::PMC::Object ();
 # Parrot::Pmc2c::Emitter.
 our $OPTIONS;
 
-$SIG{'__WARN__'} = sub { use Carp; warn $_[0]; Carp::confess; };
+# This is useful for debugging, but upgrades deprecation warnings to errors.
+#$SIG{'__WARN__'} = sub { use Carp; warn $_[0]; Carp::confess; };
 
 =head1 NAME