I have given up on compiling the game and I state the reasons. (Referring to 2.6.0 packages)
a) the English documents don't even have an INSTALL document.
b) when I take the German docs, I try to follow the instructions for GTK2. I run Ubuntu 18.04. I look for the Glib library. When I run "aptitude glib" I get a host of entries without any structure, so I don't know what to install. So I download glib-1.2.10.tar.gz from the GNOME software pages. When I try to compile these and run "./configure" I receive the following
loading cache ./config.cache
checking for a BSD compatible install... (cached) /usr/bin/install -c
checking whether build environment is sane... yes
checking whether make sets ${MAKE}... (cached) yes
checking for working aclocal... missing
checking for working autoconf... missing
checking for working automake... missing
checking for working autoheader... missing
checking for working makeinfo... missing
checking host system type... Invalid configuration `x86_64-unknown-linux-gnu': machine `x86_64-unknown' not recognized
checking build system type... Invalid configuration `x86_64-unknown-linux-gnu': machine `x86_64-unknown' not recognized
checking for ranlib... (cached) ranlib
checking for gcc... (cached) gcc
checking whether the C compiler (gcc ) works... yes
checking whether the C compiler (gcc ) is a cross-compiler... no
checking whether we are using GNU C... (cached) yes
checking whether gcc accepts -g... (cached) yes
checking for ld used by GCC... (cached) /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... (cached) yes
checking for BSD-compatible nm... (cached) /usr/bin/nm -B
checking whether ln -s works... (cached) yes
loading cache ./config.cache within ltconfig
ltconfig: you must specify a host type if you use `--no-verify'
Try `ltconfig --help' for more information.
configure: error: libtool configure failed
I have no idea how to continue, compile failed!
The German instructions say that
"Compiliert man selbst, sollte (oder muß) folgende Reihenfolge
eingehalten werden: Glib, Gtk+, Imlib".
So I'm stuck with Glib.
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My impression is that these INSTALL documents need an overhaul to meet current situations with Linux environments. To give you an idea how neatly this can be made I refer you to the Widelands build instructions which show a complete install command for dependent libraries in Ubuntu in one single line. At
https://wl.widelands.org/wiki/Building%20Widelands
sudo apt install bzr cmake g++ gcc gettext libboost-dev libboost-regex-dev libboost-test-dev libglew-dev libpng-dev libsdl2-dev libsdl2-image-dev libsdl2-mixer-dev libsdl2-net-dev libsdl2-ttf-dev python zlib1g-dev
This is an example of a clear statement and this makes life of the user/player/developer adequately easy. Is this possible for freeciv?