Changes necessary to get building on Gentoo

[jeremyd2019]

• Gentoo's build system will pass --disable-foo for options that it wants disabled, so fix it so that --disable-foo options actually disable instead of enabling things.
• The version of progsreiserfs that is currently in Gentoo's package tree has some header, function, and struct member name changes. One of the patches was written by someone else, the URL that I found it at is http://linamh.disconnected-by-peer.at/linamh/browser/sys-block/partclone/files/partclone-0.2.36-progsreiserfs-0.3.1-1.patch?rev=ea577defdd55fc399aefa7caba0dbccf8e66258d

See also my update to a bug trying to get partclone included in Gentoo's package system:
https://bugs.gentoo.org/show_bug.cgi?id=486518

[Thomas-Tsai]

thank you for this pathc, i will check amd test soon and It will be merge if everything work fine.

[Thomas-Tsai]

Sorry, this pull request is too old. Please update it again if necessary, or I will turn off this request in the future. Please forgive me.