> is it possible to build tethereal w/o linking to gtk?
Yes. Tethereal uses GLib, but not GTK+:
hostname$ ldd ./ethereal
libgtk-1.2.so.0 => /usr/local/lib/libgtk-1.2.so.0
libgdk-1.2.so.0 => /usr/local/lib/libgdk-1.2.so.0
libgmodule-1.2.so.0 => /usr/local/lib/libgmodule-1.2.so.0
libglib-1.2.so.0 => /usr/local/lib/libglib-1.2.so.0
libdl.so.1 => /usr/lib/libdl.so.1
libintl.so.1 => /usr/lib/libintl.so.1
libXext.so.0 => /usr/openwin/lib/libXext.so.0
libX11.so.4 => /usr/openwin/lib/libX11.so.4
libsocket.so.1 => /usr/lib/libsocket.so.1
libnsl.so.1 => /usr/lib/libnsl.so.1
libw.so.1 => /usr/lib/libw.so.1
libm.so.1 => /usr/lib/libm.so.1
libz.so => /usr/local/lib/libz.so
libc.so.1 => /usr/lib/libc.so.1
libdga.so.1 => /usr/openwin/lib/libdga.so.1
libmp.so.2 => /usr/lib/libmp.so.2
/usr/platform/SUNW,Ultra-Enterprise/lib/libc_psr.so.1
hostname$ ldd ./tethereal
libgmodule-1.2.so.0 => /usr/local/lib/libgmodule-1.2.so.0
libglib-1.2.so.0 => /usr/local/lib/libglib-1.2.so.0
libdl.so.1 => /usr/lib/libdl.so.1
libm.so.1 => /usr/lib/libm.so.1
libsocket.so.1 => /usr/lib/libsocket.so.1
libnsl.so.1 => /usr/lib/libnsl.so.1
libz.so => /usr/local/lib/libz.so
libc.so.1 => /usr/lib/libc.so.1
libmp.so.2 => /usr/lib/libmp.so.2
/usr/platform/SUNW,Ultra-Enterprise/lib/libc_psr.so.1
> could someone add an option to the autoconf stuff for this?
It was added a while ago. I don't remember whether, if it doesn't find
GTK+ but does find GLib, it automatically disables the build of
ethereal, or if you have to supply a "--disable-ethereal" flag to the
configure script to do so explicitly.