multimedia/dav1d: work around crashes with clang >= 12 on i386

$ ffmpeg -hide_banner -i foo.y4m -c:v libsvtav1 -y foo.ivf
$ ffmpeg -hide_banner -i foo.ivf -f null /dev/null
[libdav1d @ 0x250c2c00] libdav1d 1.0.0
[libdav1d @ 0x250c2c00] Frame size limit reduced from 2147483647 to 67108864.
Bus error

* thread #1, name = 'ffmpeg', stop reason = signal SIGBUS: hardware error
    frame #0: 0x22e8c816 libdav1d.so.6`dav1d_data_wrap(buf=0x25100390, ptr="\U00000012", sz=61259, free_callback=(libavcodec.so.58`libdav1d_data_free at libdav1d.c:189), user_data=0x250d66c0) at lib.c:734
(lldb) bt
* thread #1, name = 'ffmpeg', stop reason = signal SIGBUS: hardware error
  * frame #0: 0x22e8c816 libdav1d.so.6`dav1d_data_wrap(buf=0x25100390, ptr="\U00000012", sz=61259, free_callback=(libavcodec.so.58`libdav1d_data_free at libdav1d.c:189), user_data=0x250d66c0) at lib.c:734
    frame #1: 0x213a4c33 libavcodec.so.58`libdav1d_receive_frame(c=<unavailable>, frame=<unavailable>) at libdav1d.c:215:19
    frame #2: 0x21121082 libavcodec.so.58`decode_receive_frame_internal(avctx=0x250bfc00, frame=<unavailable>) at decode.c:546:15
    frame #3: 0x21120fd8 libavcodec.so.58`avcodec_send_packet(avctx=0x250bfc00, avpkt=0xffffd3d0) at decode.c:617:15
    frame #4: 0x20a5273d libavformat.so.58`try_decode_frame(s=<unavailable>, st=0x250f9000, avpkt=<unavailable>, options=<unavailable>) at utils.c:3084:19
    frame #5: 0x20a4fe73 libavformat.so.58`avformat_find_stream_info(ic=0x250d7000, options=0x250d61c0) at utils.c:3949:9
    frame #6: 0x00418cf6 ffmpeg`open_input_file(o=0xffffd80c, filename=<unavailable>) at ffmpeg_opt.c:1196:15
    frame #7: 0x004184c9 ffmpeg`open_files(l=<unavailable>, inout=<unavailable>, open_file=<unavailable>) at ffmpeg_opt.c:3338:15
    frame #8: 0x00418278 ffmpeg`ffmpeg_parse_options(argc=<unavailable>, argv=<unavailable>) at ffmpeg_opt.c:3378:11
    frame #9: 0x0042e6f0 ffmpeg`main(argc=7, argv=0xffffdc44) at ffmpeg.c:4988:11
    frame #10: 0x00417d0d ffmpeg`_start1(cleanup=0x204537e0, argc=7, argv=0xffffdc44) at crt1_c.c:72:7
    frame #11: 0x00417e70 ffmpeg`_start at crt1_s.S:46

$ make clean test -C graphics/libavif
[...]
45% tests passed, 6 tests failed out of 11

Total Test time (real) =  17.82 sec

The following tests FAILED:
          1 - aviftest (Bus error)
          5 - avifchangesettingtest (Bus error)
          6 - avifgridapitest (Bus error)
          7 - avifincrtest (Bus error)
          8 - avifmetadatatest (Bus error)
         11 - test_cmd (Failed)

* thread #1, name = 'aviftest', stop reason = signal SIGBUS: hardware error
    frame #0: 0x207a81f6 libdav1d.so.6`dav1d_data_wrap(buf=0xffffc7d4, ptr="\U00000012", sz=37169, free_callback=(libavif.so.15`avifDav1dFreeCallback at codec_dav1d.c:34), user_data=0x00000000) at lib.c:734
   731                      void (*const free_callback)(const uint8_t *data,
   732                                                  void *user_data),
   733                      void *const user_data)
-> 734  {
   735      return dav1d_data_wrap_internal(buf, ptr, sz, free_callback, user_data);
   736  }
   737
(lldb) bt
* thread #1, name = 'aviftest', stop reason = signal SIGBUS: hardware error
  * frame #0: 0x207a81f6 libdav1d.so.6`dav1d_data_wrap(buf=0xffffc7d4, ptr="\U00000012", sz=37169, free_callback=(libavif.so.15`avifDav1dFreeCallback at codec_dav1d.c:34), user_data=0x00000000) at lib.c:734
    frame #1: 0x204746a1 libavif.so.15`dav1dCodecGetNextImage(codec=0x215e9090, decoder=0x2182c000, sample=0x215e9060, alpha=0, isLimitedRangeAlpha=0xffffc93c, image=0x218400a0) at codec_dav1d.c:87:9
    frame #2: 0x2045c812 libavif.so.15`avifDecoderDecodeTiles(decoder=0x2182c000, nextImageIndex=0, firstTileIndex=0, tileCount=1, decodedTileCount=0x2183302c) at read.c:3853:14
    frame #3: 0x2045bf59 libavif.so.15`avifDecoderNextImage(decoder=0x2182c000) at read.c:3937:9
    frame #4: 0x004029a9 aviftest`runIOTests(dataDir="../libavif-0.11.0/tests/data/") at aviftest.c:255:54
    frame #5: 0x00402310 aviftest`main(argc=2, argv=0xffffdc0c) at aviftest.c:327:19
    frame #6: 0x00401f9d aviftest`_start1(cleanup=0x204157e0, argc=2, argv=0xffffdc0c) at crt1_c.c:72:7
    frame #7: 0x00402100 aviftest`_start at crt1_s.S:46

multimedia/dav1d/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	dav1d
 DISTVERSION=	1.0.0
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	multimedia
 
 MAINTAINER=	jbeich@FreeBSD.org

multimedia/dav1d/files/patch-i386

@@ -0,0 +1,14 @@
+https://code.videolan.org/videolan/dav1d/-/issues/408
+
+--- src/lib.c.orig	2022-03-18 13:31:21 UTC
++++ src/lib.c
+@@ -726,6 +726,9 @@ uint8_t *dav1d_data_create(Dav1dData *const buf, const
+     return dav1d_data_create_internal(buf, sz);
+ }
+
++#ifdef __i386__
++__attribute__((optnone))
++#endif
+ int dav1d_data_wrap(Dav1dData *const buf, const uint8_t *const ptr,
+                     const size_t sz,
+                     void (*const free_callback)(const uint8_t *data,