fix mingw bit calculation

Author: SchrodingerZhu

src/ds/bits.h

@@ -13,7 +13,7 @@
 #include <cstdint>
 #include <type_traits>
 #if defined(_WIN32) && defined(__GNUC__)
-#  define USE_CLZLL
+#  define USE_BIT_LL
 #endif
 #ifdef pause
 #  undef pause
@@ -76,7 +76,7 @@ namespace snmalloc
 
       return BITS - index - 1;
 #  endif
-#elif defined(USE_CLZLL)
+#elif defined(USE_BIT_LL)
       return static_cast<size_t>(__builtin_clzll(x));
 #else
       return static_cast<size_t>(__builtin_clzl(x));
@@ -142,7 +142,9 @@ namespace snmalloc
 
     inline size_t ctz(size_t x)
     {
-#if __has_builtin(__builtin_ctzl)
+#if defined(USE_BIT_LL)
+      return static_cast<size_t>(__builtin_ctzll(x));
+#elif __has_builtin(__builtin_ctzl)
       return static_cast<size_t>(__builtin_ctzl(x));
 #elif defined(_MSC_VER)
 #  ifdef SNMALLOC_VA_BITS_64