diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index ac0a0b69e64..62d441439d8 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -418,15 +418,11 @@ unpackFile() {
     header "unpacking source archive $curSrc" 3
 
     case "$curSrc" in
-        *.tar)
+        *.tar | *.tar.* | *.tgz | *.tbz2)
+	    # GNU tar can automatically select the decompression method
+	    # (info "(tar) gzip").
             tar xvf $curSrc
             ;;
-        *.tar.gz | *.tgz | *.tar.Z)
-            gzip -d < $curSrc | tar xvf -
-            ;;
-        *.tar.bz2 | *.tbz2)
-            bzip2 -d < $curSrc | tar xvf -
-            ;;
         *.zip)
             unzip $curSrc
             ;;