diff --git a/build.cm b/build.cm
index 4205a9e8..0031c83e 100644
--- a/build.cm
+++ b/build.cm
@@ -260,48 +260,50 @@ Build.build_module_dylib = function(pkg, file, target, opts) {
   var build_dir = get_build_dir()
   ensure_dir(build_dir)
   var dylib_path = build_dir + '/' + link_key + '.' + _target + dylib_ext
+  var cmd_parts = null
+  var cmd_str = null
+  var ret = null
 
-  if (fd.is_file(dylib_path))
-    return dylib_path
+  if (!fd.is_file(dylib_path)) {
+    cmd_parts = [cc, '-shared', '-fPIC']
 
-  var cmd_parts = [cc, '-shared', '-fPIC']
+    if (tc.system == 'darwin') {
+      cmd_parts = array(cmd_parts, [
+        '-undefined', 'dynamic_lookup',
+        '-Wl,-dead_strip',
+        '-Wl,-rpath,@loader_path/../local',
+        '-Wl,-rpath,' + local_dir
+      ])
+    } else if (tc.system == 'linux') {
+      cmd_parts = array(cmd_parts, [
+        '-Wl,--allow-shlib-undefined',
+        '-Wl,--gc-sections',
+        '-Wl,-rpath,$ORIGIN/../local',
+        '-Wl,-rpath,' + local_dir
+      ])
+    } else if (tc.system == 'windows') {
+      push(cmd_parts, '-Wl,--allow-shlib-undefined')
+    }
 
-  if (tc.system == 'darwin') {
-    cmd_parts = array(cmd_parts, [
-      '-undefined', 'dynamic_lookup',
-      '-Wl,-dead_strip',
-      '-Wl,-rpath,@loader_path/../local',
-      '-Wl,-rpath,' + local_dir
-    ])
-  } else if (tc.system == 'linux') {
-    cmd_parts = array(cmd_parts, [
-      '-Wl,--allow-shlib-undefined',
-      '-Wl,--gc-sections',
-      '-Wl,-rpath,$ORIGIN/../local',
-      '-Wl,-rpath,' + local_dir
-    ])
-  } else if (tc.system == 'windows') {
-    push(cmd_parts, '-Wl,--allow-shlib-undefined')
+    push(cmd_parts, '-L"' + local_dir + '"')
+    push(cmd_parts, '"' + obj + '"')
+    arrfor(_extra, function(extra_obj) {
+      push(cmd_parts, '"' + extra_obj + '"')
+    })
+    cmd_parts = array(cmd_parts, resolved_ldflags)
+    cmd_parts = array(cmd_parts, target_ldflags)
+    push(cmd_parts, '-o')
+    push(cmd_parts, '"' + dylib_path + '"')
+
+    cmd_str = text(cmd_parts, ' ')
+    log.console('Linking module ' + file + ' -> ' + fd.basename(dylib_path))
+    ret = os.system(cmd_str)
+    if (ret != 0) {
+      print('Linking failed: ' + file); disrupt
+    }
   }
 
-  push(cmd_parts, '-L"' + local_dir + '"')
-  push(cmd_parts, '"' + obj + '"')
-  arrfor(_extra, function(extra_obj) {
-    push(cmd_parts, '"' + extra_obj + '"')
-  })
-  cmd_parts = array(cmd_parts, resolved_ldflags)
-  cmd_parts = array(cmd_parts, target_ldflags)
-  push(cmd_parts, '-o')
-  push(cmd_parts, '"' + dylib_path + '"')
-
-  var cmd_str = text(cmd_parts, ' ')
-  log.console('Linking module ' + file + ' -> ' + fd.basename(dylib_path))
-  var ret = os.system(cmd_str)
-  if (ret != 0) {
-    print('Linking failed: ' + file); disrupt
-  }
-
-  // Install to deterministic lib/<pkg>/<stem>.dylib
+  // Always install to deterministic lib/<pkg>/<stem>.dylib
   // Strip .c/.cpp extension so the loader can find it by module name
   var file_stem = file
   if (ends_with(file_stem, '.cpp')) file_stem = text(file_stem, 0, -4)
diff --git a/internal/engine.cm b/internal/engine.cm
index b338acf5..b6a26349 100644
--- a/internal/engine.cm
+++ b/internal/engine.cm
@@ -382,6 +382,7 @@ os.run_ast_fn = run_ast_fn
 os.run_ast_noopt_fn = run_ast_noopt_fn
 core_extras.core_json = json
 core_extras.actor_api = $_
+core_extras.log = log
 core_extras.runtime_env = runtime_env
 core_extras.content_hash = content_hash
 core_extras.cache_path = cache_path