Add stubs for methods with file acces

Trying to load a location from a file will fail because `File` is not
yet ported to windows.

src/time/location/loader.cr

@@ -23,6 +23,9 @@ class Time::Location
 
   # :nodoc:
   def self.load_from_dir_or_zip(name : String, source : String)
+    {% if flag?(:win32) %}
+    raise NotImplementedError.new("Time::Location.load_from_dir_or_zip")
+    {% else %}
     if source.ends_with?(".zip")
       open_file_cached(name, source) do |file|
         read_zip_file(name, file) do |io|
@@ -35,6 +38,7 @@ class Time::Location
         read_zoneinfo(name, file)
       end
     end
+    {% end %}
   end
 
   private def self.open_file_cached(name : String, path : String)
@@ -57,6 +61,9 @@ class Time::Location
 
   # :nodoc:
   def self.find_zoneinfo_file(name : String, sources : Enumerable(String))
+    {% if flag?(:win32) %}
+    raise NotImplementedError.new("Time::Location.find_zoneinfo_file")
+    {% else %}
     sources.each do |source|
       if source.ends_with?(".zip")
         return source if File.exists?(source)
@@ -65,6 +72,7 @@ class Time::Location
         return source if File.exists?(path)
       end
     end
+    {% end %}
   end
 
   # Parse "zoneinfo" time zone file.