Hi!

This fixes another not NUL terminated string literal that is created
in tree-ssa-forwprop.c at simplify_builtin_call.

src_buf is set up to contain a NUL at src_buf[src_len], thus use src_len + 1
as length parameter to build_string_literal.  All other uses of
build_string_literal do it right, as far as I can see.


Bootstrapped and reg-tested on x86_64-pc-linux-gnu.
Is it OK for trunk?


Thanks
Bernd.