configure: check for lzma

Some packages are available as LZMA tarballs. LZMA is a relatively recent
compression algorithm; it's slightly better than bzip2, but offers much
faster decompression. LZMA is now deprecated in favor of XZ, but some
packages switched to LZMA when XZ was not yet available, or still in its
infancy. Latest XZ (which totaly obsoletes LZMA) offers a backward LZMA-
compatible utility, so we can check for 'lzma' nonetheless.

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

 # 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

 }