clang/llvm: Fewer build-time dependencies

Such as valgrind, dejagnu, tcl/tk, ...

pkgs/development/compilers/llvm/3.4/llvm.nix

@@ -29,8 +29,8 @@ in stdenv.mkDerivation rec {
 
   buildInputs =
     [ perl groff cmake libxml2 libffi ]
-    ++ stdenv.lib.optional (!stdenv.isDarwin) python
-    ++ stdenv.lib.optional stdenv.isLinux valgrind;
+    ++ stdenv.lib.optional (!stdenv.isDarwin) python /*
+    ++ stdenv.lib.optional stdenv.isLinux valgrind */;
 
   propagatedBuildInputs = [ ncurses zlib ];
 

pkgs/development/libraries/libffi/default.nix

@@ -16,7 +16,8 @@ stdenv.mkDerivation rec {
     "--with-gcc-arch=generic" # no detection of -march= or -mtune=
   ] ++ stdenv.lib.optional (stdenv.needsPax) "--enable-pax_emutramp";
 
-  doCheck = stdenv.isLinux; # until we solve dejagnu problems on darwin and expect on BSD
+  #doCheck = stdenv.isLinux; # until we solve dejagnu problems on darwin and expect on BSD
+  doCheck = false;
 
   dontStrip = stdenv ? cross; # Don't run the native `strip' when cross-compiling.