scripts/functions: only use one download program

Currently, we use either wget or curl, whichever is installed.
In case both are installed, both are used. This means that it
takes a while trying all extensions.

Remove use of wget, and use only curl.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # Compute sparc-specific values

 CT_DoArchTupleValues() {

     # That's the only thing to override

     if [ "${CT_ARCH_64}" = "y" ]; then

         CT_TARGET_ARCH="${CT_ARCH}64"

     fi

 }