xml-config accepts the following options:
--version
Print the currently installed version of GNOME-XML on the standard output.
--libs Print the linker flags that are necessary to link a GNOME-XML program. Add --dynamic after
--libs to print only shared library linking information.
--cflags
Print the compiler flags that are necessary to compile a GNOME-XML program.
--prefix=PREFIX
If specified, use PREFIX instead of the installation prefix that GNOME-XML was built with when
computing the output for the --cflags and --libs options. This option must be specified before
any --libs or --cflags options.