Replace __builtin_ctzl with a new ctz function in bit_ops.h

1 files changed, 1 insertions, 1 deletions

diff --git a/src/numthry.cpp b/src/numthry.cpp
index 9f05b6114..ffd523e82 100644
--- a/src/numthry.cpp
+++ b/src/numthry.cpp
@@ -86,7 +86,7 @@ u32bit low_zero_bits(const BigInt& n)
 
          if(x)
             {
-            low_zero += __builtin_ctzl(x);
+            low_zero += ctz(x);
             break;
             }
          else