libc/eglibc: Add option that allows for getting svn over http://

Instead of getting eglibc over standard svn://svn.eglibc.org
Add an option that allows the user to get source from
http://www.eglibc.org/svn

This is useful if you are behind a firewall or proxy.
If you are behind a proxy, don't forget to configure
${HOME}/.subversion/servers

In the [global] section setup your proxy configuration.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[yann.morin.1998@anciens.enib.fr: removed useless 'default n']
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # Compute Alpha-specific values

 CT_DoArchTupleValues () {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}${CT_ARCH_ALPHA_VARIANT}"

 }