diff --git a/pkgs/development/interpreters/perl-5.10/default.nix b/pkgs/development/interpreters/perl-5.10/default.nix
index 8f7908a8097..a8b8dd536a7 100644
--- a/pkgs/development/interpreters/perl-5.10/default.nix
+++ b/pkgs/development/interpreters/perl-5.10/default.nix
@@ -34,14 +34,10 @@ stdenv.mkDerivation {
   preConfigure =
     ''
       configureFlags="$configureFlags -Dprefix=$out -Dman1dir=$out/share/man/man1 -Dman3dir=$out/share/man/man3"
-
+      
       if test "$NIX_ENFORCE_PURITY" = "1"; then
-        case $system in
-          *-linux)  LIBC=$(cat $NIX_GCC/nix-support/orig-libc) ;;
-          *-darwin) LIBC=/usr ;;
-          *)        echo unsupported system $system; exit 1 ;;
-        esac
-        configureFlags="$configureFlags -Dlocincpth=$LIBC/include -Dloclibpth=$LIBC/lib"
+        GLIBC=$(cat $NIX_GCC/nix-support/orig-libc)
+        configureFlags="$configureFlags -Dlocincpth=$GLIBC/include -Dloclibpth=$GLIBC/lib"
       fi
     '';
 
diff --git a/pkgs/development/interpreters/perl-5.8/builder.sh b/pkgs/development/interpreters/perl-5.8/builder.sh
index 500de901e17..79458b3249b 100644
--- a/pkgs/development/interpreters/perl-5.8/builder.sh
+++ b/pkgs/development/interpreters/perl-5.8/builder.sh
@@ -1,12 +1,8 @@
 source $stdenv/setup
 
 if test "$NIX_ENFORCE_PURITY" = "1"; then
-    case $system in
-        *-linux)  LIBC=$(cat $NIX_GCC/nix-support/orig-libc) ;;
-        *-darwin) LIBC=/usr ;;
-        *)        echo unsupported system $system; exit 1 ;;
-    esac
-    extraflags="-Dlocincpth=$LIBC/include -Dloclibpth=$LIBC/lib"
+    GLIBC=$(cat $NIX_GCC/nix-support/orig-libc)
+    extraflags="-Dlocincpth=$GLIBC/include -Dloclibpth=$GLIBC/lib"
 fi
 
 configureScript=./Configure
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 0433fff06ae..538be82c612 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -2254,19 +2254,18 @@ let
     inherit (bleedingEdgeRepos) sourceByName;
   };
 
-  supportsPerl = stdenv.isLinux || system == "i686-darwin";
+  perl = if !stdenv.isLinux then sysPerl else perlReal;
 
-  perl = if !supportsPerl then sysPerl else
-    import ../development/interpreters/perl-5.10 {
-      fetchurl = fetchurlBoot;
-      inherit stdenv;
-  };
-
-  perl58 = if !supportsPerl then sysPerl else
+  perl58 = if !stdenv.isLinux then sysPerl else
     import ../development/interpreters/perl-5.8 {
       inherit fetchurl stdenv;
     };
 
+  perlReal = import ../development/interpreters/perl-5.10 {
+    fetchurl = fetchurlBoot;
+    inherit stdenv;
+  };
+
   # FIXME: unixODBC needs patching on Darwin (see darwinports)
   phpOld = import ../development/interpreters/php {
     inherit stdenv fetchurl flex bison libxml2 apacheHttpd;