OS : Red Hat Enterprise Linux 8.0 (Ootpa)
uname -m : x86_64

You've probably used wrong revisions for submodules or something.

If you download sources from github, better use git clone, not wget https://github.com/MariaDB/server/archive.
If you don't need the history, use --depth 1

Or download sources from downloads.mariadb.org — then you won't need git at all.

@Sergei Golubchik Thanks for quick reply. As per your comment I have tried both ways:
i) git clone
ii) download sources from downloads.mariadb.org
But I am still facing the same build failure. Any help would be appreciated.

Please find below steps that I followed:
first way :
cd $SOURCE_ROOT/
git clone https://github.com/MariaDB/server.git
cd server
git checkout mariadb-10.4.6
git submodule update --init --recursive
mkdir $SOURCE_ROOT/build_mariadb
cd $SOURCE_ROOT/build_mariadb
cmake $SOURCE_ROOT/mariadb-10.4.6
make

second way :
wget https://mirror.its.dal.ca/mariadb//mariadb-10.4.6/source/mariadb-10.4.6.tar.gz
tar xzf mariadb-10.4.6.tar.gz
mkdir $SOURCE_ROOT/build_mariadb
cd $SOURCE_ROOT/build_mariadb
cmake $SOURCE_ROOT/mariadb-10.4.6
make

Okay, so if you're getting the same failure, it should be

CMake Error at /home/test/server-mariadb-10.4.6/cmake/do_abi_check.cmake:81 (MESSAGE):

  ABI check found difference between

  /home/test/server-mariadb-10.4.6/include/mysql/plugin_audit.h.pp and

  /home/test/build_mariadb/abi_check.out

Could you please diff them manually? Just paste or attach the output of

diff -u /home/test/server-mariadb-10.4.6/include/mysql/plugin_audit.h.pp /home/test/build_mariadb/abi_check.out

May be a truncated output, if it's long.
Thanks!

@Sergei Golubchik Now I could build mariadb in fresh RHEL 8.0 container using both ways that you have suggested.
The above build failure(with both ways) was observed as I had used previously built mariadb folder(cmake $SOURCE_ROOT/mariadb-10.4.6) unknowingly.
Thanks...

I am reopening the "bug", or rather usability error. This is still happening on latest MariaDB and googling on the error brings up thousands of pages where people complain about it.

The root cause is that the binary 'diff' is missing from the system, and CMake gets an exit code which it thinks was from diff, but in reality it was that diff was not even found.

Workaround: apt/yum install diffutils

Proper fix: extend CMake code to check for binary diff and emit a proper error message if it was not found at all

serg Fix available at https://github.com/MariaDB/server/pull/1846, please merge.

otto, how did you know that the root cause was missing diff? I wasn't able to find it any hints in the logs.

serg Because Vittal posted his exact steps and nothing in them installs diffutils. He tried to compile MariaDB out of pristine sources and this is what happens 100% of the time if one does so without diffutils. See my PR for proof.

Vittal never replied to your request to diff the files. It would have most likely shown that there is no diff, but diff itself was missing.

This error message has 1600 hits on Google, it is very common. But it is fixed now from 10.6 onwards if you approve my PR.

Pushed. Thanks, otto!