fix for compile issue encountered in https://github.com/rvm/rvm/issues/4000

rubyvm.patch

diff --git a/random.c b/random.c
index e669e98..9334921 100644
--- a/random.c
+++ b/random.c
@@ -521,7 +521,7 @@ fill_random_bytes_syscall(void *seed, size_t size, int unused)
     CryptGenRandom(prov, size, seed);
     return 0;
 }
-#elif defined __linux__ && defined SYS_getrandom
+#elif defined __linux__ && defined __NR_getrandom
 #include <linux/random.h>
 
 # ifndef GRND_NONBLOCK
@@ -538,7 +538,7 @@ fill_random_bytes_syscall(void *seed, size_t size, int need_secure)
  if (!need_secure)
      flags = GRND_NONBLOCK;
  errno = 0;
- ret = syscall(SYS_getrandom, seed, size, flags);
+ ret = syscall(__NR_getrandom, seed, size, flags);
  if (errno == ENOSYS) {
      ATOMIC_SET(try_syscall, 0);
      return -1;