Readd BtrFS-progs 3.16 for snapper build

pkgs/tools/filesystems/btrfsprogs/3.16.nix

@@ -0,0 +1,31 @@
+{ stdenv, fetchurl, attr, acl, zlib, libuuid, e2fsprogs, lzo
+, asciidoc, xmlto, docbook_xml_dtd_45, docbook_xsl, libxslt }:
+
+let version = "3.16"; in
+
+stdenv.mkDerivation rec {
+  name = "btrfs-progs-${version}";
+
+  src = fetchurl {
+    url = "mirror://kernel/linux/kernel/people/kdave/btrfs-progs/btrfs-progs-v${version}.tar.xz";
+    sha256 = "0phbrgipl04q8cdj9nnshik7b6p2bg51jxb3l1gvfc04dkgm2xls";
+  };
+
+  buildInputs = [
+    attr acl zlib libuuid e2fsprogs lzo
+    asciidoc xmlto docbook_xml_dtd_45 docbook_xsl libxslt
+  ];
+
+  # for btrfs to get the rpath to libgcc_s, needed for pthread_cancel to work
+  NIX_CFLAGS_LINK = "-lgcc_s";
+
+  makeFlags = "prefix=$(out)";
+
+  meta = with stdenv.lib; {
+    description = "Utilities for the btrfs filesystem";
+    homepage = https://btrfs.wiki.kernel.org/;
+    license = licenses.gpl2;
+    maintainers = with maintainers; [ raskin wkennington ];
+    platforms = platforms.linux;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -642,6 +642,7 @@ let
   bsod = callPackage ../misc/emulators/bsod { };
 
   btrfsProgs = callPackage ../tools/filesystems/btrfsprogs { };
+  btrfsProgs-3_16 = callPackage ../tools/filesystems/btrfsprogs/3.16.nix { };
 
   bwm_ng = callPackage ../tools/networking/bwm-ng { };
 
@@ -10503,7 +10504,9 @@ let
 
   smartdeblur = callPackage ../applications/graphics/smartdeblur { };
 
-  snapper = callPackage ../tools/misc/snapper { };
+  snapper = callPackage ../tools/misc/snapper { 
+    btrfsProgs = btrfsProgs-3_16;
+  };
 
   snd = callPackage ../applications/audio/snd { };