Support git+https:// remotes

[kpcyrd]

In case of Arch Linux, a source= entry can be specified in this format:

git+https://github.com/ncmpcpp/ncmpcpp.git#tag=0.9.2

When discovering something like this, the repo should be cloned with --depth 1 and then exported into tar format through:

git -C source-code/ -c tar.tar.gz.command="gzip -cn" archive --prefix="ncmpcpp-0.9.2/" -o "ncmpcpp-0.9.2.tar.gz" "0.9.2"