Audacious

Short answer, yes, you need GLib. It provides various low-level utilities (portable file access, stable sort, main loop, etc.) and has very few dependencies; you certainly don't need to install GTK+ or any of the rest of GNOME.

OK. Thanks. I see that gio and gobject and some others are necessary for dbus, and dbus is necessary for audtool.

So my main problem is that the cross-compiler does not provide glib, so configure does not set up extra.mk pointing to it.

I tried installing libglib2.0-dev and linux-libc-dev from debian into the cross compiler tree, but extra.mk is still incorrect. Maybe the wrong versions or the position in the tree is wrong. Hand-editing paths in extra.mk causes multiple other failures.

I need a better compiler.

I got a better compiler from linaro. I can now compile audacious - but not link it - see the end of this post.

This is my configure:

./configure CFLAGS="-nostdlib  --sysroot=/opt/linaro -isystem/opt/linaro/arm-linux-gnueabihf/libc/usr/include -march=armv7" LDFLAGS="-nostdlib  
-L/opt/linaro/arm-linux-gnueabihf/libc/usr/lib -L/opt/linaro/usr/lib/arm-linux-gnueabihf/ -L/opt/linaro/usr/lib/arm-linux-gnueabihf/glib-2.0/include 
-Wl,-rpath,/opt/linaro/lib/arm-linux-gnueabihf  -Wl,-rpath,/opt/linaro/usr/lib/arm-linux-gnueabihf" --disable-qt --disable-gtk --build i686-pc-linux-gnu 
--host arm-linux-gnueabihf

However, I then have to amend extra.mk manually. It contains:

GIO_CFLAGS ?= -pthread -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include 
GIO_LIBS ?= -lgio-2.0 -lgobject-2.0 -lglib-2.0 
GLIB_CFLAGS ?= -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include 
GLIB_LIBS ?= -lglib-2.0 
GMODULE_CFLAGS ?= -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include 
GMODULE_LIBS ?= -Wl,--export-dynamic -lgmodule-2.0 -pthread -lglib-2.0 

I have to change those -I path references to point to directories in my cross compiler tree, the files having come from debian armhf.

GIO_CFLAGS ?= -pthread -I/opt/linaro/usr/include/gio-unix-2.0/ -I/opt/linaro/usr/include/glib-2.0 -I/opt/linaro/usr/lib/arm-linux-gnueabihf/glib-2.0/include 
...
GLIB_CFLAGS ?= -I/opt/linaro/usr/include/glib-2.0 
...
GMODULE_CFLAGS ?= -pthread -I/opt/linaro/usr/include/glib-2.0 
...

I suspect that these /usr paths are from environment variables; I haven't changed any for cross-compiling - I've used CFLAGS and LDFLAGS to set paths, including -nostdlib which I think should prevent it using any default library paths.

What should I do to get extra.mk to point to the correct cross-compiler paths?

Anyway, if I correct extra.mk it compiles:

Entering directory src.
Entering directory dbus.
Successfully generated dependencies.
Successfully compiled aud-dbus.c.
Successfully linked aud-dbus.a.
Leaving directory dbus.
Entering directory audtool.
Successfully generated dependencies.
Successfully compiled main.c.
Successfully compiled handlers_general.c.
Successfully compiled handlers_playback.c.
Successfully compiled handlers_playlist.c.
Successfully compiled handlers_playqueue.c.
Successfully compiled handlers_vitals.c.
Successfully compiled handlers_equalizer.c.
Successfully compiled report.c.
Successfully compiled wrappers.c.
/opt/linaro/bin/../lib/gcc/arm-linux-gnueabihf/7.2.1/../../../../arm-linux-gnueabihf/bin/ld: /opt/linaro/usr/lib/arm-linux-gnueabihf//libglib-2.0.a(libglib_2_0_la-gstrfuncs.o): undefined reference to symbol 'strtoull_l@@GLIBC_2.4'
/opt/linaro/bin/../arm-linux-gnueabihf/libc/lib/libc.so.6: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
Failed to link audtool!
../../buildsys.mk:207: recipe for target 'audtool' failed

Any idea about that error? I do have libc.so.6:
/opt/linaro/arm-linux-gnueabihf/libc/lib/libc.so.6