[BUG][HOWTO] dkms doesn't build on Oracle Linux 8.8 UEKR7 kernel UEK 5.15

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I recently went into this while attempting what should have been an usual 10 minute install following the docs. It does build for the RHCK kernel, but not for the UEK kernel:

checking kernel source directory... /usr/src/kernels/5.15.0-102.110.5.el8uek.x86_64
checking kernel build directory... /usr/src/kernels/5.15.0-102.110.5.el8uek.x86_64
checking kernel source version... 5.15.0-102.110.5.el8uek.x86_64
checking for kernel config option compatibility... done
checking whether CONFIG_MODULES is defined... no
configure: error:
                *** This kernel does not include the required loadable module
                *** support!
                ***
                *** To build OpenZFS as a loadable Linux kernel module
                *** enable loadable module support by setting
                *** `CONFIG_MODULES=y` in the kernel configuration and run
                *** `make modules_prepare` in the Linux source tree.
                ***
                *** If you don't intend to enable loadable kernel module
                *** support, please compile OpenZFS as a Linux kernel built-in.
                ***
                *** Prepare the Linux source tree by running `make prepare`,
                *** use the OpenZFS `--enable-linux-builtin` configure option,
                *** copy the OpenZFS sources into the Linux source tree using
                *** `./copy-builtin <linux source directory>`,
                *** set `CONFIG_ZFS=y` in the kernel configuration and compile
                *** kernel as usual.

This is a misleading message, do not chase that rabbit hole!

Instead the root cause is when installing the build environment, the distro pulls in gcc-8.5 but the UEK kernel is built using gcc-11 (this host where I experienced it is a minimal OL8.8 setup with OLVM node role enabled. don't remember if UEKR7 was pulled in by OLVM setup or if UEKR6 is default - there is a matrix somewhere on oracle website about what UEK is default on what release)

Further digging into https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/developing_c_and_cpp_applications_in_rhel_8/additional-toolsets-for-development_developing-applications leads to the following solution to make ZoL install into the latest UEKR7 kernel on OL8.8 (it works fine on OL9 because UEKR7 and distro have the same gcc version!)

$ scl run gcc-toolset-11 bash
$ sudo -E dkms autoinstall

I also am not sure why I did dnf install libuuid-devel libblkid-devel libtirpc-devel libaio-devel (at first after invoking scl, I went into /usr/src/zfs-2.1.12 and ,anually invoked the ./configure script and noticed it complained about these libs missing) and why there were not pulled automatically earlier.

I hope this helps someone hitting the same issue.

Cheers

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related #13625