sox, ffmpeg_svn expressions added

ghcPkgUtil defines a function to create setup-hook 
- creating a packagedatabase (nix-support/package.conf)
- adding it to GHC_PACKAGE_PATH
see comments for details

svn path=/nixpkgs/trunk/; revision=9500

pkgs/development/libraries/haskell/generic/ghcPkgUtil.sh

@@ -0,0 +1,33 @@
+# mantainer: Marc Weber (marco-oweber@gmx.de)
+#
+# example usage: add ghcPkgUtil to buildInputs then somewhere in buildPhase:
+#
+#  createEmptyPackageDatabaseAndSetupHook
+#  configure --with-package-db=$PACKAGE_DB
+#  ... compile ghc library ...
+# add your library to propagatedBuildInputs instead of buildInputs 
+# in all depending libraries
+
+
+
+# creates a setup hook
+# adding the package database 
+# nix-support/package.conf to GHC_PACKAGE_PATH
+# if not already contained
+setupHookRegisteringPackageDatabase(){
+  ensureDir $out/nix-support;
+  local pkgdb=$out/nix-support/package.conf
+  cat >> $out/nix-support/setup-hook << EOF
+    
+    echo \$GHC_PACKAGE_PATH | grep -l $pkgdb &> /dev/null || \
+      export GHC_PACKAGE_PATH=\$GHC_PACKAGE_PATH\${GHC_PACKAGE_PATH:+$PATH_DELIMITER}$pkgdb;
+EOF
+}
+
+# create an empty package database in which the new library can be registered. 
+createEmptyPackageDatabaseAndSetupHook(){
+  ensureDir $out/nix-support;
+  PACKAGE_DB=$out/nix-support/package.conf;
+  echo '[]' > $PACKAGE_DB";
+  setupHookRegisteringPackageDatabase
+}