## function unpack_source

#### Main purpose

Decompress the requested tarball inside the SRC_DIR.

#### Notes

Archive decompression is complicated since src2pkg supports several very different types of archives as 'source' input -including binary content which is structured within Linux File System Hierarchy and rpm archives which sometimes contain one or more compressed archives which must be decompressed. src2pkg 'recognizes' these formats as it works and decides what to do.
Once the archive is decompressed src2pkg has its' first chance to see what the content might be. unpack_source calls an internal function which looks at the content to see if it is binary content or some sort of source code. Basically it looks for a linux-type directory structure with directories like etc, usr, opt, bin or other. It also looks for rpm .spec files, debian control files or install directories. If it finds this type of content it will be treated as binary content and later copied into the PKG_DIR and corrected instead of configuring and compiling it(these steps will be skipped).
If the archive appears to contain source it will be further analyzed by later functions.