No <glob.h> in the Android NDK

So don't bother building libxml2 programs for Android, we have no need for
them, there is no way to run them on normal devices, etc. While at it, don't
bother with scripts, manpages or "data" either. We just want the library.

Change-Id: Ic6553c4ed5b51feab40fed6bd62fd10795e9acf9