[Buildroot] Making --localstatedir=/var global?

[Daniel Nyström]

I see many packages defines localstatedir to point at /var - what do
you think about making it a global default by putting it in
Makefile.autotools.in?

There are a few exceptions though:
dhcp/dhcp.mk: defines localstatedir to /var/lib/dhcp
links/links.mk: defines localstatedir to /tmp
proftpd/proftpd.mk: defines localstatedir to /var/run

All of these are (AFAIK) errornous use of the localstatedir variable,
and could be corrected using patches instead.

Thoughts?