QT 5.12 EGLFS Raspberry Pi detection inconsistent

[ThatGuyYeah]

Alright, thanks for helping with the first issue, now I am running to an issue that seems to be (and the main issue I am helping a friend with trying to solve).

I am trying to add QT to a Raspberry Pi 3 B+ on Raspbian using these instructions: https://www.tal.org/tutorials/building-qt-512-raspberry-pi

I am up to the part where I configure the QT build using pretty much this command:

PKG_CONFIG_LIBDIR=/usr/lib/arm-linux-gnueabihf/pkgconfig:/usr/share/pkgconfig
/home/pi/qt-everywhere-src-5.12.3/configure -platform linux-rpi-g++
-v
-opengl es2 -eglfs
-no-gtk
-opensource -confirm-license -release
-reduce-exports
-force-pkg-config
-nomake tests -nomake examples -no-compile-examples
-skip qtwayland
-skip qtwebengine
-no-feature-geoservices_mapboxgl
-qt-pcre
-no-pch
-ssl
-evdev
-system-freetype
-fontconfig
-glib
-prefix /opt/Qt5.12
-qpa eglfs

This command does a configure summary that displays this:

QPA backends:
DirectFB ............................... no
EGLFS .................................. yes
EGLFS details:
..
EGLFS Raspberry Pi ................... yes
EGLFS X11 ............................ yes

Now, if I try and do the configure command again via \home\pi\qt-everywhere-src-5.12.3\configure, I end up with this:

QPA backends:
DirectFB ............................... no
EGLFS .................................. yes
EGLFS details:
..
EGLFS Raspberry Pi ................... no
EGLFS X11 ............................ yes

So pretty much, I have a schrodinger's cat going on here. I am suspecting I am not doing the Missing EGLFS Fix correctly but will take any take any help.

EDIT: I did some tinkering and I used the command sudo /home/pi/qt-everywhere-src-5.12.3/configure -platform linux-rpi-g++ and it looks like adding the platform worked out as it says it consistently. But doing it without that platform prefix makes it no.

Not sure if that was my issue but would like a better explanation of the situation.