GCC 10 available for testing etc. in -current.

[matthew green <mrg%eterna.com.au@localhost>]

hi folks.


(please reply privately to this spams-many-lists message, and
i will keep src/external/gpl3/gcc/README.gcc10 updated with
the latest status.)


i've just commited the final parts that make most platforms build
(and many run) with GCC 10 as the system compiler.

i've tested these systems:
	- amd64
	- sparc (qemu)
	- sparc64
	- shark
	- evbarmv7hf (cubietruck)
	- i386 (has a signal delivery issue, but that seems to
	  have been introduced last year, however, things seem
	  to be equally as functional/broken.)
	- ia64 (ski boots as far as before)
	- mipsel (malta gxemul)
	- mips64 (either big or little endian)
	- sh3-el (landisk gxemul)
	- vax (simh)

so i'm after testing for these targets:

	- alpha
	- hppa
	- powerpc
	- sh3-eb
	- arm32-eb
	- mipseb
	- m68k

there are still issues for these targets:
	- arm64 -- 'LSE' extension issues, likely needs both
	  fixes for libgcc and kernel work
	- sun2 ramdisk overflows, and it's already at the limit
	  of what can boot without crashing from lack of space
	- x68k 'loadbsd' program appears to pull in TLS code from
	  libc and does not link.

the steps are fairly simple:

- update -currnet srcs
- build.sh with no -u (update), and set -V HAVE-GCC=10 as a
  option.  this ensures that everything is actually rebuilt
  with the new compiler.
- install new kernel/userland and perform testing.  if you can
  run atf that would be great, but other tests are useful too.
- reply to this message with results.

thanks!


.mrg.