diff --git a/setup.py b/setup.py
index f06b011d5..35c726d89 100644
--- a/setup.py
+++ b/setup.py
@@ -6,7 +6,7 @@
 from distutils.command.build_ext import build_ext
 from distutils.command.build_scripts import build_scripts
 from distutils.command.install_lib import install_lib
-from distutils.sysconfig import get_config_vars
+from distutils.sysconfig import get_config_var
 from platform import architecture
 from subprocess import Popen, CalledProcessError, PIPE, check_call
 from glob import glob
@@ -183,15 +183,22 @@ def _build_monoclr(self, ext):
                                         depends=ext.depends)
 
         output_dir = os.path.dirname(self.get_ext_fullpath(ext.name))
-        py_libs = get_config_vars("BLDLIBRARY")[0]
+        py_libs = get_config_var("BLDLIBRARY")
         libs += " " + py_libs
 
+        # Include the directories python's shared libs were installed to. This
+        # is case python was built with --enable-shared as then npython will need
+        # to be able to find libpythonX.X.so.
+        runtime_library_dirs = (get_config_var("DESTDIRS") or "").split(" ")
+        if ext.runtime_library_dirs:
+            runtime_library_dirs.extend(ext.runtime_library_dirs)
+
         self.compiler.link_executable(objects,
                                       _npython_exe,
                                       output_dir=output_dir,
                                       libraries=self.get_libraries(ext),
                                       library_dirs=ext.library_dirs,
-                                      runtime_library_dirs=ext.runtime_library_dirs,
+                                      runtime_library_dirs=runtime_library_dirs,
                                       extra_postargs=libs.split(" "),
                                       debug=self.debug)
 
diff --git a/src/runtime/assemblymanager.cs b/src/runtime/assemblymanager.cs
index 291301466..583b5c945 100644
--- a/src/runtime/assemblymanager.cs
+++ b/src/runtime/assemblymanager.cs
@@ -30,7 +30,6 @@ internal class AssemblyManager {
         static ResolveEventHandler rhandler;
         static Dictionary<string, int> probed;
         static List<Assembly> assemblies;
-        static Dictionary<string, Assembly> loadedAssemblies;
         internal static List<string> pypath;
 
         private AssemblyManager() {}
@@ -47,7 +46,6 @@ internal static void Initialize() {
             probed = new Dictionary<string, int>(32);
             //generics = new Dictionary<string, Dictionary<string, string>>();
             assemblies = new List<Assembly>(16);
-            loadedAssemblies = new Dictionary<string, Assembly>();
             pypath = new List<string>(16);
 
             AppDomain domain = AppDomain.CurrentDomain;
@@ -204,24 +202,25 @@ public static Assembly LoadAssemblyPath(string name) {
             string path = FindAssembly(name);
             Assembly assembly = null;
             if (path != null) {
-                if (loadedAssemblies.ContainsKey(path)) {
-                    return loadedAssemblies[path];
-                }
-                // Avoid using Assembly.LoadFrom as referenced assemblies that exist
-                // in the same path will be loaded directly from there, rather than
-                // using other versions already loaded. This is a problem if there
-                // is a Python.Runtime.dll in the same folder as the assembly being
-                // loaded, as that will result in two instances being loaded.
-                try   {
-                    byte[] bytes = System.IO.File.ReadAllBytes(path);
-                    assembly = Assembly.Load(bytes);
-                    loadedAssemblies[path] = assembly;
-                }
+                try   { assembly = Assembly.LoadFrom(path); }
                 catch {}
             }
             return assembly;
         }
 
+        //===================================================================
+        // Returns an assembly that's already been loaded
+        //===================================================================
+
+        public static Assembly FindLoadedAssembly(string name) {
+            for (int i = 0; i < assemblies.Count; i++) {
+                Assembly a = (Assembly)assemblies[i];
+                if (a.GetName().Name == name) {
+                    return a;
+                }
+            }
+            return null;
+        }
 
         //===================================================================
         // Given a qualified name of the form A.B.C.D, attempt to load 
@@ -247,7 +246,10 @@ public static bool LoadImplicit(string name, bool warn=true) {
                     if (assemblies == null) {
                         assemblies = new HashSet<Assembly>(AppDomain.CurrentDomain.GetAssemblies());
                     }
-                    Assembly a = LoadAssemblyPath(s);
+                    Assembly a = FindLoadedAssembly(s);
+                    if (a == null) {
+                        a = LoadAssemblyPath(s);
+                    }
                     if (a == null) {
                         a = LoadAssembly(s);
                     }
diff --git a/src/runtime/moduleobject.cs b/src/runtime/moduleobject.cs
index efa916464..c5735ca4a 100644
--- a/src/runtime/moduleobject.cs
+++ b/src/runtime/moduleobject.cs
@@ -385,7 +385,11 @@ public static Assembly AddReference(string name)
         {
             AssemblyManager.UpdatePath();
             Assembly assembly = null;
-            assembly = AssemblyManager.LoadAssemblyPath(name);
+            assembly = AssemblyManager.FindLoadedAssembly(name);
+            if (assembly == null)
+            {
+                assembly = AssemblyManager.LoadAssemblyPath(name);
+            }
             if (assembly == null)
             {
                 assembly = AssemblyManager.LoadAssembly(name);