configure: add support for new CPUs

Add new -march values for Intel CPUs (introduced with GCC 4.9.x), add support
for the missing AMD btver* CPUs, and improve SunCC flags accordingly.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/hevc_cabac: decrease CABAC_MAX_BIN

Prevents shifts with undefined behavior

Fixes CID1206634
Fixes CID1206635
Fixed CID1206636

Reviewed-by: smarter
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>