oss4-dkms fails to build on Focal

ubuntu@dryden:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal

ubuntu@dryden:~$ uname -a
Linux dryden 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:22:04 UTC 2020 ppc64le ppc64le ppc64le GNU/Linux

ubuntu@dryden:~$ sudo apt install oss4-dkms
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  oss4-dkms
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/651 kB of archives.
After this operation, 4920 kB of additional disk space will be used.
Selecting previously unselected package oss4-dkms.
(Reading database ... 100504 files and directories currently installed.)
Preparing to unpack .../oss4-dkms_4.2-build2010-5ubuntu5_ppc64el.deb ...
Unpacking oss4-dkms (4.2-build2010-5ubuntu5) ...
Setting up oss4-dkms (4.2-build2010-5ubuntu5) ...
Loading new oss4-4.2-build2010 DKMS files...
Building for 5.4.0-42-generic
Building initial module for 5.4.0-42-generic
ERROR: Cannot create report: [Errno 17] File exists: '/var/crash/oss4-dkms.0.crash'
Error! Bad return status for module build on kernel: 5.4.0-42-generic (ppc64le)
Consult /var/lib/dkms/oss4/4.2-build2010/build/make.log for more information.
dpkg: error processing package oss4-dkms (--configure):
 installed oss4-dkms package post-installation script subprocess returned error exit status 10
Errors were encountered while processing:
 oss4-dkms
E: Sub-process /usr/bin/dpkg returned an error code (1)

buntu@dryden:~$ cat /var/lib/dkms/oss4/4.2-build2010/build/make.log
DKMS make.log for oss4-4.2-build2010 for kernel 5.4.0-42-generic (ppc64le)
Fri Aug 14 09:15:43 UTC 2020
make: Entering directory '/usr/src/linux-headers-5.4.0-42-generic'
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/os_linux.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_ac97.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_audio_core.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_audiofmt.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_grc3.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_spdif.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_default_timer.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_core.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_mapper.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_parser.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_queue.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_timers.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_stubs.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_mixer_core.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_core_options.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_core_services.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_memblk.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_remux.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_sndstat.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/vmix_core.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/vmix_input.o
  CC [M] /var/lib/dkms/oss4/4.2-build2010/build/core/vmix_output.o
In file included from /var/lib/dkms/oss4/4.2-build2010/build/core/oss_config.h:39,
                 from /var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.c:19:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.c: In function ‘uart401_status’:
/var/lib/dkms/oss4/4.2-build2010/build/core/os.h:175:22: error: implicit declaration of function ‘__inb’ [-Werror=implicit-function-declaration]
  175 | #define INB(osdev,a) __inb(a)
      | ^~~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.c:31:10: note: in expansion of macro ‘INB’
   31 | return INB (devc->osdev, STATPORT);
      | ^~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.c: In function ‘uart401_cmd’:
/var/lib/dkms/oss4/4.2-build2010/build/core/os.h:179:27: error: implicit declaration of function ‘__outb’ [-Werror=implicit-function-declaration]
  179 | #define OUTB(osdev, d, a) __outb(d, a)
      | ^~~~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.c:39:3: note: in expansion of macro ‘OUTB’
   39 | OUTB (devc->osdev, cmd, COMDPORT);
      | ^~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_parser.c: In function ‘do_midi_msg’:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_parser.c:89:14: warning: this statement may fall through [-Wimplicit-fallthrough=]
   89 | msg[2] = 64;
      | ~~~~~~~^~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_midi_parser.c:91:5: note: here
   91 | case 0x80:
      | ^~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/os_linux.c: In function ‘osdev_create_201911151618’:
/var/lib/dkms/oss4/4.2-build2010/build/core/os_linux.c:162:10: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  162 | devpath = oss_pci_read_devpath (osdev->dip);
      | ^
cc1: some warnings being treated as errors
make[1]: *** [scripts/Makefile.build:273: /var/lib/dkms/oss4/4.2-build2010/build/core/oss_uart401.o] Error 1
make[1]: *** Waiting for unfinished jobs....
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c: In function ‘oss_virt_to_bus’:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:118:10: error: implicit declaration of function ‘virt_to_bus’; did you mean ‘virt_to_phys’? [-Werror=implicit-function-declaration]
  118 | return virt_to_bus (addr);
      | ^~~~~~~~~~~
      | virt_to_phys
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c: In function ‘oss_timer_callback’:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:519:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
  519 | unsigned long id = tmout->id;
      | ^~~~~~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c: At top level:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:1161:19: error: field ‘s’ has incomplete type
 1161 | struct DIstruct s;
      | ^
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c: In function ‘__udivmoddi4’:
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:1331:4: error: implicit declaration of function ‘count_leading_zeros’ [-Werror=implicit-function-declaration]
 1331 | count_leading_zeros (bm, d0);
      | ^~~~~~~~~~~~~~~~~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:1434:5: error: implicit declaration of function ‘sub_ddmmss’ [-Werror=implicit-function-declaration]
 1434 | sub_ddmmss (n1, n0, n1, n0, d1, d0);
      | ^~~~~~~~~~
/var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.c:1462:8: error: implicit declaration of function ‘umul_ppmm’ [-Werror=implicit-function-declaration]
 1462 | umul_ppmm (m1, m0, q0, d0);
      | ^~~~~~~~~
cc1: some warnings being treated as errors
make[1]: *** [scripts/Makefile.build:273: /var/lib/dkms/oss4/4.2-build2010/build/core/oss_core.o] Error 1
make: *** [Makefile:1731: /var/lib/dkms/oss4/4.2-build2010/build/core] Error 2
make: Leaving directory '/usr/src/linux-headers-5.4.0-42-generic'