diff --git a/src/libmain/setuid-common.hh b/src/libmain/setuid-common.hh
deleted file mode 100644
index a3e840996..000000000
--- a/src/libmain/setuid-common.hh
+++ /dev/null
@@ -1,22 +0,0 @@
-/* Code shared between libmain and nix-setuid-helper. */
-
-extern char * * environ;
-
-
-namespace nix {
-    
-
-void setuidCleanup()
-{
-    /* Don't trust the environment. */
-    environ = 0;
-
-    /* Make sure that file descriptors 0, 1, 2 are open. */
-    for (int fd = 0; fd <= 2; ++fd) {
-        struct stat st;
-        if (fstat(fd, &st) == -1) abort();
-    }
-}
-
- 
-}
diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index fa72ca5bc..d7fb24019 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -14,9 +14,6 @@
 #include <aterm2.h>
 
 
-#include "setuid-common.hh"
-
-
 namespace nix {
 
 
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index b152dc8f4..fb6411408 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -17,6 +17,9 @@
 #include "util.hh"
 
 
+extern char * * environ;
+
+
 namespace nix {
 
 
@@ -818,6 +821,19 @@ void quickExit(int status)
 }
 
 
+void setuidCleanup()
+{
+    /* Don't trust the environment. */
+    environ = 0;
+
+    /* Make sure that file descriptors 0, 1, 2 are open. */
+    for (int fd = 0; fd <= 2; ++fd) {
+        struct stat st;
+        if (fstat(fd, &st) == -1) abort();
+    }
+}
+
+
 //////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index b850ee798..8f79ec9be 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -237,6 +237,10 @@ string runProgram(Path program);
    Cygwin, _exit() doesn't seem to do the right thing.) */
 void quickExit(int status);
 
+/* Common initialisation for setuid programs: clear the environment,
+   sanitize file handles 0, 1 and 2. */
+void setuidCleanup();
+
 
 /* User interruption. */
 
diff --git a/src/nix-setuid-helper/main.cc b/src/nix-setuid-helper/main.cc
index dc0b2cd6c..26cdc73b7 100644
--- a/src/nix-setuid-helper/main.cc
+++ b/src/nix-setuid-helper/main.cc
@@ -12,11 +12,12 @@
 
 #include "util.hh"
 
-#include "../libmain/setuid-common.hh"
-
 using namespace nix;
 
 
+extern char * * environ;
+
+
 /* Recursively change the ownership of `path' to user `uidTo' and
    group `gidTo'.  `path' must currently be owned by user `uidFrom',
    or, if `uidFrom' is -1, by group `gidFrom'. */