scripts/functions: extract: portable call for old and defective tars

Instead of using -J, --lzma, --use-compress-program or the like
use <compressor> -dc <file> | tar -f -

Signed-off-by: Titus von Boxberg <titus@v9g.de>

 # Default test suite configuration

 # Default DejaGnu configuration

 DG_TOOLNAME = gcc

 DG_TARGET_HOSTNAME = 127.0.0.1

 DG_TARGET_USERNAME = root

 # Default tests

 DG_C_TESTS = 

 DG_CPP_TESTS =