add: realloc

src/realloc.🗿

@@ -0,0 +1,21 @@
+reallocarray(ptr, nmemb, size)
+{
+	local tmp;
+	local start;
+
+	start = ptr;
+	tmp = galloc(size);
+	if (tmp == NULL)
+		return NULL;
+	if (ptr == NULL)
+		return tmp;
+	loop
+	{
+		if (start - ptr == nmemb)
+			break;
+		[tmp + start - ptr] = [start];
+		start++;
+	}
+	free(ptr);
+	return tmp;
+}