Does not compile on Fedora 34 with kernel 5.11

[j1cken]

Step 2: Describe your environment

• v4l2loopback version: _____

'master' git pull from 2021-03-08
commit cee0a688b7fefaf6620bfc1dd319d9d55da41af7 (HEAD -> master, origin/master, origin/HEAD)

• kernel version: _____

    uname -a
  

Linux fedora 5.11.3-300.fc34.x86_64 #1 SMP Thu Mar 4 19:03:18 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

• Distribution (+version): _____

    lsb_release -a
  

LSB Version:	:core-4.1-amd64:core-4.1-noarch
Distributor ID:	Fedora
Description:	Fedora release 34 (Thirty Four)
Release:	34
Codename:	ThirtyFour

Step 3: Describe the problem:

Steps to reproduce:

1. make clean && make

Observed Results:

• What happened? This could be a description, log output, etc.

rm -f *~
rm -f Module.symvers Module.markers modules.order
make -C /lib/modules/`uname -r`/build M=/home/torben/development/v4l2loopback clean
make[1]: Entering directory '/usr/src/kernels/5.11.3-300.fc34.x86_64'
make[1]: Leaving directory '/usr/src/kernels/5.11.3-300.fc34.x86_64'
Building v4l2-loopback driver...
make -C /lib/modules/`uname -r`/build M=/home/torben/development/v4l2loopback modules
make[1]: Entering directory '/usr/src/kernels/5.11.3-300.fc34.x86_64'
  CC [M]  /home/torben/development/v4l2loopback/v4l2loopback.o
cc1: error: incompatible gcc/plugin versions
cc1: error: failed to initialize plugin ./scripts/gcc-plugins/structleak_plugin.so
make[2]: *** [scripts/Makefile.build:279: /home/torben/development/v4l2loopback/v4l2loopback.o] Error 1
make[1]: *** [Makefile:1801: /home/torben/development/v4l2loopback] Error 2
make[1]: Leaving directory '/usr/src/kernels/5.11.3-300.fc34.x86_64'
make: *** [Makefile:43: v4l2loopback.ko] Error 2

Expected Results:

• What did you expect to happen?

Successful compilation

Relevant Code:

see log output above

[umlaeute]

cc1: error: incompatible gcc/plugin versions

that looks very much like a problem with your installed gcc.
make sure you have the same compiler used for building the kernel

can you build other out-of-tree modules?

[umlaeute]

and please use a full commitish rather than "master git pull from today". today is a fickle thing, and it's not so much fun tracking down a problem if you first have to find out when the OP created the ticket.

[kwizart]

https://ask.fedoraproject.org/t/fedora-34-beta-and-oot-kmod-nvidia-virtualbox-v4l2loopback-etc/12778

This should work:
dnf donwgrade gcc