Fixed potential memory leak

Create a wrapper object first, then buffer allocation which can
fail.

compile.c

@@ -9721,12 +9721,13 @@ static VALUE
 pinned_list_new(long size)
 {
     struct pinned_list * ptr;
+    VALUE obj_list =
+        TypedData_Make_Struct(0, struct pinned_list, &pinned_list_type, ptr);
 
-    ptr = xmalloc(sizeof(struct pinned_list));
-    ptr->size = size;
     ptr->buffer = xcalloc(size, sizeof(VALUE));
+    ptr->size = size;
 
-    return TypedData_Wrap_Struct(0, &pinned_list_type, ptr);
+    return obj_list;
 }
 
 static ibf_offset_t

lib/rubygems/installer.rb

@@ -189,6 +189,7 @@ class Gem::Installer
     if options[:user_install]
       @gem_home = Gem.user_dir
       @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
+      @plugins_dir = Gem.plugindir(gem_home)
       check_that_user_bin_dir_is_in_path
     end
   end