[Updated] Script for preparing full kernel sources in lieu of headers

[coreplayer2]

linux-kernel-sources-env script has been updated to add latest Busybox compatibility

The attached script has been tested in tinycore-8.2 kernel 4.8.17 and tinycorepure64-8.2 kernel 4.8.17, linux-kernel-sources-env.tcz extension will be submitted asap.  Meanwhile download attached script, make executable and run.