Remove double quote for MRUBY_XXX in libmruby.flags.mak

tasks/libmruby.rake

@@ -2,17 +2,17 @@ MRuby.each_target do
   file libfile("#{build_dir}/lib/libmruby") => libmruby.flatten do |t|
     archiver.run t.name, t.prerequisites
     open("#{build_dir}/lib/libmruby.flags.mak", 'w') do |f|
-      f.puts 'MRUBY_CFLAGS = "%s"' % cc.all_flags.gsub('"', '\\"') 
+      f.puts 'MRUBY_CFLAGS = %s' % cc.all_flags.gsub('"', '\\"') 
 
       gem_flags = gems.map { |g| g.linker.flags }
       gem_library_paths = gems.map { |g| g.linker.library_paths }
-      f.puts 'MRUBY_LDFLAGS = "%s"' % linker.all_flags(gem_library_paths, gem_flags).gsub('"', '\\"') 
+      f.puts 'MRUBY_LDFLAGS = %s' % linker.all_flags(gem_library_paths, gem_flags).gsub('"', '\\"') 
 
       gem_flags_before_libraries = gems.map { |g| g.linker.flags_before_libraries }
-      f.puts 'MRUBY_LDFLAGS_BEFORE_LIBS = "%s"' % [linker.flags_before_libraries, gem_flags_before_libraries].flatten.join(' ').gsub('"', '\\"') 
+      f.puts 'MRUBY_LDFLAGS_BEFORE_LIBS = %s' % [linker.flags_before_libraries, gem_flags_before_libraries].flatten.join(' ').gsub('"', '\\"') 
 
       gem_libraries = gems.map { |g| g.linker.libraries }
-      f.puts 'MRUBY_LIBS = "%s"' % linker.library_flags(gem_libraries).gsub('"', '\\"') 
+      f.puts 'MRUBY_LIBS = %s' % linker.library_flags(gem_libraries).gsub('"', '\\"') 
     end
   end
 end