No, I did not use --prefix=/usr, which I did not find in the github readme.

So, it's good now, but so I know for next time, why don't run ./configure as root?  And, where are the instructions to use --prefix=/usr?  And, where those permissions sufficient?

And did you use

as stated in the build instructions?

@stopAI

You can get all dependencies of xfce4-terminal with simple command:

apt build-dep xfce4-terminal

Thanks for this!  After this, I was able to build xfce4-terminal (I think).

NEVER run

 ./configure

as root.

Just run it as regular user.

Could you explain this?  When I run as user, I get:

./configure: line 1941: config.log: Permission denied
./configure: line 1951: config.log: Permission denied

But when run as root (as in the github readme), it completes.

So, after this, I ran make and make install.  Apart from several errors about things being deprecated, it appeared to complete successfully.  But I can't seem to find/run this new version.

In the build directory, there is a terminal/ directory, in which there is a xfce4-terminal executable file, which is three times the size of the old one.  But when I run this file, I get the old version 1.0.4 terminal.

whereis xfce4-terminal gives two results:  /usr/bin/ and /usr/local/bin/.  The former appears to be the old executable (dated 2022-05-24), and the latter appears to be the same as in the build/terminal/ directory (dated today, 2024-02-29) and almost three times the size of the former.  But running any of them just gives the old 1.0.4 terminal.

So, not sure where to go from here.

@boughtonp, backporting may be helpful for other users as well, but not convinced that it should be left in the hands of a beginner. 

I am unclear as to your suggestion:

Add Devuan Testing repos to existing Devaun installation, or

Install Devuan Testing in VM?

I was suggesting running Devuan Testing in a VM to confirm that the v1.1.1 provides what you want.

I have also yet to properly checkout how backports are created - though the link fsmithred provided probably provides that information (and there looks to be a simpler guide at //wiki.debian.org/SimpleBackportCreation for personal use) - but the first step is confirming there's a suitable version in Debian/Devuan repos, hence why the suggestion to try the version Devuan Testing provides.

apt build-dep xfce4-terminal

P.S.

NEVER run

 ./configure

as root.

Just run it as regular user.

So I apt searched for liblibxfce4ui-2-dev and installed it. The other missing was a "vte"-package.
I'm on Devaun 5 too and have build-essential and linux-headers-xx installed since a long time.

When compiling one must consider that often times the source Readme does not mention ALL necessary libs needed.

Add Devuan Testing repos to existing Devaun installation, or

Install Devuan Testing in VM?

Getting it backported makes sense, but I am complete unaware how to do that?

Since Devuan Testing has v1.1.1, a sensible first step would be to test that in a VM and see if it does have the desired functionality. If so, looking into what it might take to get that version backported would be worth checking.

In xfce4-terminal 1.1.2, the first four of those are now editable in the Preferences dialog; unfortunately, the last two are still not available for editing.

If I knew how, I could simply patch the 1.0.4 binary, but I haven't a clue how to do that, or whether it is even possible.

Ready to pass on building from source on this distro, but certainly willing to continue if any further help is forthcoming.  I'm going to have to learn to do this sooner or later.

A better way would be to backport xfce4-terminal and make a deb package so that your package manager knows about it.
https://wiki.debian.org/BuildingFormalBackports

Either way, you might need to build more packages to satisfy dependencies.

I think you got better advice in the first reply.