support file extension .cpp/.cxx in mrbgem and tool

Rakefile

@@ -41,7 +41,7 @@ depfiles = MRuby.targets['host'].bins.map do |bin|
     FileUtils.rm_f t.name, { :verbose => $verbose }
     FileUtils.cp t.prerequisites.first, t.name, { :verbose => $verbose }
   end
-  
+
   install_path
 end
 
@@ -53,7 +53,7 @@ MRuby.each_target do |target|
 
     gem.bins.each do |bin|
       exec = exefile("#{build_dir}/bin/#{bin}")
-      objs = Dir.glob("#{current_dir}/tools/#{bin}/*.c").map { |f| objfile(f.pathmap("#{current_build_dir}/tools/#{bin}/%n")) }
+      objs = Dir.glob("#{current_dir}/tools/#{bin}/*.{c,cpp,cxx}").map { |f| objfile(f.pathmap("#{current_build_dir}/tools/#{bin}/%n")) }
 
       file exec => objs + [libfile("#{build_dir}/lib/libmruby")] do |t|
         gem_flags = gems.map { |g| g.linker.flags }

tasks/mrbgem_spec.rake

@@ -6,7 +6,7 @@ module MRuby
     class << self
       attr_accessor :current
     end
-    LinkerConfig = Struct.new(:libraries, :library_paths, :flags, :flags_before_libraries, :flags_after_libraries) 
+    LinkerConfig = Struct.new(:libraries, :library_paths, :flags, :flags_before_libraries, :flags_after_libraries)
 
     class Specification
       include Rake::DSL
@@ -53,13 +53,13 @@ module MRuby
         @linker = LinkerConfig.new([], [], [], [])
 
         @rbfiles = Dir.glob("#{dir}/mrblib/*.rb").sort
-        @objs = Dir.glob("#{dir}/src/*.{c,cpp,m,asm,S}").map do |f|
+        @objs = Dir.glob("#{dir}/src/*.{c,cpp,cxx,m,asm,S}").map do |f|
           objfile(f.relative_path_from(@dir).to_s.pathmap("#{build_dir}/%X"))
         end
         @objs << objfile("#{build_dir}/gem_init")
 
         @test_rbfiles = Dir.glob("#{dir}/test/*.rb")
-        @test_objs = Dir.glob("#{dir}/test/*.{c,cpp,m,asm,S}").map do |f|
+        @test_objs = Dir.glob("#{dir}/test/*.{c,cpp,cxx,m,asm,S}").map do |f|
           objfile(f.relative_path_from(dir).to_s.pathmap("#{build_dir}/%X"))
         end
         @test_preload = 'test/assert.rb'
@@ -211,7 +211,7 @@ module MRuby
       end
 
       # ~> compare algorithm
-      # 
+      #
       # Example:
       #    ~> 2.2   means >= 2.2.0 and < 3.0.0
       #    ~> 2.2.0 means >= 2.2.0 and < 2.3.0