Use FFI::MemoryPointer instead of libc's malloc()

FFI provides a memory allocator class, so that there's no need to call malloc() directly.

Author: larskanis

lib/sassc/native.rb

@@ -34,7 +34,6 @@ module Native
     require_relative "native/sass_input_style"
     require_relative "native/sass_output_style"
     require_relative "native/string_list"
-    require_relative "native/lib_c"
 
     # Remove the redundant "sass_" from the beginning of every method name
     def self.attach_function(*args)
@@ -53,10 +52,9 @@ def self.return_string_array(ptr)
     end
 
     def self.native_string(string)
-      string = "#{string}\0"
-      data = Native::LibC.malloc(string.bytesize)
-      data.write_string(string)
-      data
+      m = FFI::MemoryPointer.from_string(string)
+      m.autorelease = false
+      m
     end
 
     require_relative "native/native_context_api"

lib/sassc/native/lib_c.rb

@@ -185,9 +185,9 @@ def test_custom_importer
         funct = FFI::Function.new(:pointer, [:pointer, :pointer, :pointer]) do |url, prev, cookie|
           list = Native.make_import_list(2)
 
-          str = "$var: 5px;\0"
-          data = Native::LibC.malloc(str.size)
-          data.write_string(str)
+          str = "$var: 5px;"
+          data = FFI::MemoryPointer.from_string(str)
+          data.autorelease = false
 
           entry0 = Native.make_import_entry("fake_includ.scss", data, nil)
           entry1 = Native.make_import_entry("not_included.scss", nil, nil)