misc: do not use "tar cf - |tar xf -"

Using this: tar cf - -C "/some/place" |tar xf - -C "/some/other/place"
to copy a directory to another place does not properly fail (when it does).

Using this instead: cp -av "/some/place" "/some/other/place"
makes it easy to see why and how it failed.

Impacted:
libc/uClibc
debug/ltrace
tools/sstrip
scripts/populate

 # Compute AVR32-specific values

 CT_DoArchTupleValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}"

     # gcc ./configure flags

     CT_ARCH_WITH_ARCH=

     CT_ARCH_WITH_ABI=

     CT_ARCH_WITH_CPU=

     CT_ARCH_WITH_TUNE=

     CT_ARCH_WITH_FPU=

     CT_ARCH_WITH_FLOAT=

     CT_TARGET_SYS=none

 }