random-util: use gcc's bit_RDRND definition if it exists

diff --git a/src/basic/random-util.c b/src/basic/random-util.c
index de29e07549e7136f0c13b1c93d5e94fdb3a285b3..205d5501e5187c318a0bf8e24bccf8466bab06b4 100644 (file)
--- a/src/basic/random-util.c
+++ b/src/basic/random-util.c
@@ -45,7 +45,12 @@ int rdrand(unsigned long *ret) {
                         return -EOPNOTSUPP;
                 }
 
-                have_rdrand = !!(ecx & (1U << 30));
+/* Compat with old gcc where bit_RDRND didn't exist yet */
+#ifndef bit_RDRND
+#define bit_RDRND (1U << 30)
+#endif
+
+                have_rdrand = !!(ecx & bit_RDRND);
         }
 
         if (have_rdrand == 0)