Fix $lex = chomp $lex regression from 5.12

Commit 2f9970be0 (5.13.9) caused the lhs to be written to with 0
before the chomp happens, and then incremented for each chomp on the
rhs argument.

That makes

    my $a = $/ = 7;
    $a = chomp $a;
    print $a;

print 0 instead of 1 and makes

    my $a = $/ = 0;
    $a = chomp $a;

assign the empty string to $a instead of 1.

1 files changed, 1 insertions, 1 deletions

diff --git a/proto.h b/proto.h
index ee8ba004d3..6d020121c9 100644
--- a/proto.h
+++ b/proto.h
@@ -6471,7 +6471,7 @@ PERL_STATIC_NO_RET void	S_usage(pTHX)
 
 #endif
 #if defined(PERL_IN_PP_C)
-STATIC void	S_do_chomp(pTHX_ SV *retval, SV *sv, bool chomping)
+STATIC size_t	S_do_chomp(pTHX_ SV *retval, SV *sv, bool chomping)
 			__attribute__nonnull__(pTHX_1)
 			__attribute__nonnull__(pTHX_2);
 #define PERL_ARGS_ASSERT_DO_CHOMP	\