diff --git a/pkgs/development/libraries/skalibs/default.nix b/pkgs/development/libraries/skalibs/default.nix
index e8b3403df40..349e5582013 100644
--- a/pkgs/development/libraries/skalibs/default.nix
+++ b/pkgs/development/libraries/skalibs/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.3.7.0";
+  version = "2.3.9.0";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/skalibs";
     rev = "refs/tags/v${version}";
-    sha256 = "11k84vckwvxphjswqxv677p6riyb2hgx1kh15f865hnk8n21fldx";
+    sha256 = "1c5ap14f2yr3izz8s1blgp5g4r898kzppay7xrga2j216i51zfpw";
   };
 
   dontDisableStatic = true;
@@ -23,7 +23,14 @@ in stdenv.mkDerivation rec {
     "--libdir=\${prefix}/lib"
     "--includedir=\${prefix}/include"
     "--sysdepdir=\${prefix}/lib/skalibs/sysdeps"
-  ] ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ]);
+  ]
+  ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ])
+  # On darwin, the target triplet from -dumpmachine includes version number, but
+  # skarnet.org software uses the triplet to test binary compatibility.
+  # Explicitly setting target ensures code can be compiled against a skalibs
+  # binary built on a different version of darwin.
+  # http://www.skarnet.org/cgi-bin/archive.cgi?1:mss:623:heiodchokfjdkonfhdph
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://skarnet.org/software/skalibs/;
diff --git a/pkgs/os-specific/linux/s6-linux-utils/default.nix b/pkgs/os-specific/linux/s6-linux-utils/default.nix
index faf5106c67e..c6065dbfca2 100644
--- a/pkgs/os-specific/linux/s6-linux-utils/default.nix
+++ b/pkgs/os-specific/linux/s6-linux-utils/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.0.2.0";
+  version = "2.0.2.3";
 
 in stdenv.mkDerivation rec {
 
@@ -10,7 +10,7 @@ in stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "http://www.skarnet.org/software/s6-linux-utils/${name}.tar.gz";
-    sha256 = "0y6dq4wb5v1c6ps6a7jyq08r2pjksrvz6n3dnfa9c91gzm4m1dxb";
+    sha256 = "1hwc3dmqh4cyhx9b4gd48yvjrwmfkz968rncpqc511krpfwzyngr";
   };
 
   dontDisableStatic = true;
diff --git a/pkgs/tools/misc/execline/default.nix b/pkgs/tools/misc/execline/default.nix
index 7478b1e33ee..1726afca0d0 100644
--- a/pkgs/tools/misc/execline/default.nix
+++ b/pkgs/tools/misc/execline/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.1.4.0";
+  version = "2.1.4.5";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/execline";
     rev = "refs/tags/v${version}";
-    sha256 = "1ih0mmkra3aa697nz7haaifq2hfy3wjj39npxzg9zr37m7yw67yz";
+    sha256 = "1k4db9iyskrqf6wbc4dkiqgpn0wb43qc9rf1br7kvy9rrzq3yrj0";
   };
 
   dontDisableStatic = true;
@@ -25,7 +25,9 @@ in stdenv.mkDerivation rec {
     "--with-include=${skalibs}/include"
     "--with-lib=${skalibs}/lib"
     "--with-dynlib=${skalibs}/lib"
-  ] ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ]);
+  ]
+  ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ])
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://skarnet.org/software/execline/;
diff --git a/pkgs/tools/misc/s6-portable-utils/default.nix b/pkgs/tools/misc/s6-portable-utils/default.nix
index 0ca0774989d..70b36222cca 100644
--- a/pkgs/tools/misc/s6-portable-utils/default.nix
+++ b/pkgs/tools/misc/s6-portable-utils/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.0.5.2";
+  version = "2.0.5.3";
 
 in stdenv.mkDerivation rec {
 
@@ -10,7 +10,7 @@ in stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "http://www.skarnet.org/software/s6-portable-utils/${name}.tar.gz";
-    sha256 = "0d5dvqz61abr4m2n10by8hccvw51jdvyckvpbbq0c57viri54jzm";
+    sha256 = "029fg9c37vwh9yagd69h8r192nrx4mfva8dwgpm1gxkdssrh3gi7";
   };
 
   dontDisableStatic = true;
@@ -20,7 +20,8 @@ in stdenv.mkDerivation rec {
     "--with-include=${skalibs}/include"
     "--with-lib=${skalibs}/lib"
     "--with-dynlib=${skalibs}/lib"
-  ];
+  ]
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://www.skarnet.org/software/s6-portable-utils/;
diff --git a/pkgs/tools/networking/s6-dns/default.nix b/pkgs/tools/networking/s6-dns/default.nix
index 233425dc3a1..8715cb0c45c 100644
--- a/pkgs/tools/networking/s6-dns/default.nix
+++ b/pkgs/tools/networking/s6-dns/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.0.0.4";
+  version = "2.0.0.7";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/s6-dns";
     rev = "refs/tags/v${version}";
-    sha256 = "0h2s0r0g0qi74aw04c0jap09yjzzprwc6ihknx8bqgbzv08yv03w";
+    sha256 = "033pijilkvj3vw94aqrvavr4mqafm7kcc8ql8lc3ma6lqkx4xyak";
   };
 
   dontDisableStatic = true;
@@ -25,7 +25,9 @@ in stdenv.mkDerivation rec {
     "--with-include=${skalibs}/include"
     "--with-lib=${skalibs}/lib"
     "--with-dynlib=${skalibs}/lib"
-  ] ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ]);
+  ]
+  ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ])
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://www.skarnet.org/software/s6-dns/;
diff --git a/pkgs/tools/networking/s6-networking/default.nix b/pkgs/tools/networking/s6-networking/default.nix
index 5f24592f030..603b2f61551 100644
--- a/pkgs/tools/networking/s6-networking/default.nix
+++ b/pkgs/tools/networking/s6-networking/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.1.0.1";
+  version = "2.1.0.4";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/s6-networking";
     rev = "refs/tags/v${version}";
-    sha256 = "0jdjxwqrp7lzdb85sp1gdkm7s478wyl7wqxb3jfxflgh2bgdgvy2";
+    sha256 = "1mvsiiv2zk1mbhway5q593xzjzd3lyzdqg85wrpvv791mv0kk8m9";
   };
 
   dontDisableStatic = true;
@@ -32,7 +32,8 @@ in stdenv.mkDerivation rec {
     "--with-dynlib=${execline}/lib"
     "--with-dynlib=${s6}/lib"
     "--with-dynlib=${s6Dns}/lib"
-  ];
+  ]
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://www.skarnet.org/software/s6-networking/;
diff --git a/pkgs/tools/system/s6-rc/default.nix b/pkgs/tools/system/s6-rc/default.nix
index a3b244d875b..35763e8212e 100644
--- a/pkgs/tools/system/s6-rc/default.nix
+++ b/pkgs/tools/system/s6-rc/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "0.0.1.0";
+  version = "0.0.2.1";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/s6-rc";
     rev = "refs/tags/v${version}";
-    sha256 = "02ppsda8pg7mph3r7lrh7dhi6ip99bgghsl3lf902cg9i4n50q6q";
+    sha256 = "0x9ghi1f7zqphzlzyz67z7n7mnnyxf1hghi2wa2f8cdl70nfdi2f";
   };
 
   dontDisableStatic = true;
@@ -29,7 +29,9 @@ in stdenv.mkDerivation rec {
     "--with-dynlib=${skalibs}/lib"
     "--with-dynlib=${execline}/lib"
     "--with-dynlib=${s6}/lib"
-  ] ++ [ (if stdenv.isDarwin then "--disable-shared" else "--enable-shared") ];
+  ]
+  ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ])
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   meta = {
     homepage = http://skarnet.org/software/s6-rc/;
diff --git a/pkgs/tools/system/s6/default.nix b/pkgs/tools/system/s6/default.nix
index 5e29c20339c..e1e30de5799 100644
--- a/pkgs/tools/system/s6/default.nix
+++ b/pkgs/tools/system/s6/default.nix
@@ -2,7 +2,7 @@
 
 let
 
-  version = "2.2.1.0";
+  version = "2.2.4.3";
 
 in stdenv.mkDerivation rec {
 
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
   src = fetchgit {
     url = "git://git.skarnet.org/s6";
     rev = "refs/tags/v${version}";
-    sha256 = "1g8gr3znxj8lyqpwrmgzh47yb64zldrvvvgpp1m4pb37k5k11bj9";
+    sha256 = "0j981xslcsra8filaawgwq6daqvxxjs0014lqb7dy3qf7c5pc4l8";
   };
 
   dontDisableStatic = true;
@@ -26,7 +26,9 @@ in stdenv.mkDerivation rec {
     "--with-lib=${execline}/lib"
     "--with-dynlib=${skalibs}/lib"
     "--with-dynlib=${execline}/lib"
-  ] ++ [ (if stdenv.isDarwin then "--disable-shared" else "--enable-shared") ];
+  ]
+  ++ (if stdenv.isDarwin then [ "--disable-shared" ] else [ "--enable-shared" ])
+  ++ (stdenv.lib.optional stdenv.isDarwin "--target=${stdenv.system}");
 
   preBuild = ''
     substituteInPlace "src/daemontools-extras/s6-log.c" \