Use rb_enc_str_new instead of rb_enc_str_new_cstr.

The latter in combination with strndup() would leak large amounts of memory.

ext/liboga/lexer.rl

@@ -13,7 +13,7 @@ void oga_xml_lexer_callback(
 )
 {
   int length   = te - ts;
-  VALUE value  = rb_enc_str_new_cstr(strndup(ts, length), encoding);
+  VALUE value  = rb_enc_str_new(ts, length, encoding);
   VALUE method = rb_intern(name);
 
   rb_funcall(self, method, 1, value);

ext/liboga/liboga.h

@@ -3,7 +3,6 @@
 
 #include <ruby.h>
 #include <ruby/encoding.h>
-#include <string.h>
 #include <malloc.h>
 #include <stdio.h>