[Buildroot] bug for libid3tag Config.in

[Stuart Wood]

I believe that the libid3tag Config.in needs

    select BR2_PACKAGE_ZLIB 

Added to it. Otherwise you get an error that zlib
Is missing when compiling libid3tag.
My system is ARM920T, OABI, uClibc 0.9.29,
Binutils 2.16.1, gcc 3.4.6.

Stuart