fix "libc}/lib" and similar references

Done mostly without any verification.
I didn't bother with libc}/include, as the path is still correct.

pkgs/applications/virtualization/virtualbox/default.nix

@@ -78,8 +78,8 @@ in stdenv.mkDerivation {
         -e 's@MKISOFS --version@MKISOFS -version@' \
         -e 's@PYTHONDIR=.*@PYTHONDIR=${if pythonBindings then python else ""}@' \
         -i configure
-    ls kBuild/bin/linux.x86/k* tools/linux.x86/bin/* | xargs -n 1 patchelf --set-interpreter ${stdenv.glibc}/lib/ld-linux.so.2
-    ls kBuild/bin/linux.amd64/k* tools/linux.amd64/bin/* | xargs -n 1 patchelf --set-interpreter ${stdenv.glibc}/lib/ld-linux-x86-64.so.2
+    ls kBuild/bin/linux.x86/k* tools/linux.x86/bin/* | xargs -n 1 patchelf --set-interpreter ${stdenv.glibc.out}/lib/ld-linux.so.2
+    ls kBuild/bin/linux.amd64/k* tools/linux.amd64/bin/* | xargs -n 1 patchelf --set-interpreter ${stdenv.glibc.out}/lib/ld-linux-x86-64.so.2
     find . -type f -iname '*makefile*' -exec sed -i -e 's/depmod -a/:/g' {} +
     sed -e 's@"libasound.so.2"@"${alsaLib}/lib/libasound.so.2"@g' -i src/VBox/Main/xml/Settings.cpp src/VBox/Devices/Audio/alsa_stubs.c
     export USER=nix

pkgs/applications/virtualization/virtualbox/guest-additions/default.nix

@@ -63,10 +63,10 @@ stdenv.mkDerivation {
     for i in sbin/VBoxService bin/{VBoxClient,VBoxControl} lib/VBoxGuestAdditions/mount.vboxsf
     do
         ${if stdenv.system == "i686-linux" then ''
-          patchelf --set-interpreter ${stdenv.glibc}/lib/ld-linux.so.2 $i
+          patchelf --set-interpreter ${stdenv.glibc.out}/lib/ld-linux.so.2 $i
         ''
         else if stdenv.system == "x86_64-linux" then ''
-          patchelf --set-interpreter ${stdenv.glibc}/lib/ld-linux-x86-64.so.2 $i
+          patchelf --set-interpreter ${stdenv.glibc.out}/lib/ld-linux-x86-64.so.2 $i
         ''
         else throw ("Architecture: "+stdenv.system+" not supported for VirtualBox guest additions")
         }