Bug#943555: wireguard-dkms: Kernel modules don't build with kernel 5.3.0-1-arm64 on Raspberry Pi3

[Chris.]

Package: wireguard-dkms
Version: 0.0.20191012-1
Severity: grave
Justification: renders package unusable

Dear Maintainer,

on Raspberry Pi3 kernel module stops building since updating to kernel
5.3.0.1.

Output of /var/lib/dkms/wireguard/0.0.20191012/build/make.log
DKMS make.log for wireguard-0.0.20191012 for kernel 5.3.0-1-arm64 (aarch64)
Sat Oct 26 12:37:31 UTC 2019
make: Entering directory '/usr/src/linux-headers-5.3.0-1-arm64' 
arch/arm64/Makefile:58: *** arm-linux-gnueabihf-gcc not found, check 
CROSS_COMPILE_COMPAT.  Stop.
make: *** [/usr/src/linux-headers-5.3.0-1-common/Makefile:179: sub-make] Error 2
make: Leaving directory '/usr/src/linux-headers-5.3.0-1-arm64'

Thanks.
Chris.


-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: arm64 (aarch64)

Kernel: Linux 5.3.0-1-arm64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_CRAP
Locale: LANG=de_DE.utf8, LC_CTYPE=C.UTF-8 (charmap=locale: Cannot set 
LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8), LANGUAGE=de_DE.utf8 (charmap=locale: Cannot set LC_MESSAGES to default 
locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages wireguard-dkms depends on:
ii  dkms  2.7.1-4
ii  perl  5.30.0-8

Versions of packages wireguard-dkms recommends:
ii  wireguard-tools  0.0.20191012-1

wireguard-dkms suggests no packages.

-- debconf information:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_CTYPE = "C.UTF-8",
        LANG = "de_DE.utf8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

-- debsums errors found:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_CTYPE = "C.UTF-8",
        LANG = "de_DE.utf8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").