random.c: unnecessary declarations

* random.c (random_ulong_limited, random_ulong_limited_big):
  remove unnecessary extern declarations.  rb_num_negative_p is
  declared in internal.h now.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54936 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

random.c

@@ -987,7 +987,6 @@ static unsigned long
 random_ulong_limited(VALUE obj, rb_random_t *rnd, unsigned long limit)
 {
     if (!rnd) {
-	extern int rb_num_negative_p(VALUE);
 	VALUE lim = ulong_to_num_plus_1(limit);
 	VALUE v = rb_to_int(rb_funcall2(obj, id_rand, 1, &lim));
 	unsigned long r = NUM2ULONG(v);
@@ -1006,7 +1005,6 @@ static VALUE
 random_ulong_limited_big(VALUE obj, rb_random_t *rnd, VALUE vmax)
 {
     if (!rnd) {
-	extern int rb_num_negative_p(VALUE);
 	VALUE lim = rb_big_plus(vmax, INT2FIX(1));
 	VALUE v = rb_to_int(rb_funcall2(obj, id_rand, 1, &lim));
 	if (rb_num_negative_p(v)) {