The following patch attempts to use the diagnostics URL support if available
to provide more information about the C++17 empty base and C++20
[[no_unique_address]] empty class ABI changes in -Wpsabi diagnostics.
in GCC 10.1 at the end of the diagnostics is then in some terminals
underlined with a dotted line and points to a (to be written) anchor in
gcc-10/changes.html which we need to write anyway.
2020-04-29 Jakub Jelinek <jakub@redhat.com>
* configure.ac (-with-changes-root-url): New configure option,
defaulting to https://gcc.gnu.org/.
* Makefile.in (CFLAGS-opts.o): Define CHANGES_ROOT_URL for
opts.c.
* pretty-print.c (get_end_url_string): New function.
(pp_format): Handle %{ and %} for URLs.
(pp_begin_url): Use pp_string instead of pp_printf.
(pp_end_url): Use get_end_url_string.
* opts.h (get_changes_url): Declare.
* opts.c (get_changes_url): New function.
* config/rs6000/rs6000-call.c: Include opts.h.
(rs6000_discover_homogeneous_aggregate): Use %{in GCC 10.1%} instead
of just in GCC 10.1 in diagnostics and add URL.
* config/arm/arm.c (aapcs_vfp_is_call_or_return_candidate): Likewise.
* config/aarch64/aarch64.c (aarch64_vfp_is_call_or_return_candidate):
Likewise.
* config/s390/s390.c (s390_function_arg_vector,
s390_function_arg_float): Likewise.
* configure: Regenerated.
* c-format.c (PP_FORMAT_CHAR_TABLE): Add %{ and %}.
