diff --git a/inc/defs.hh b/inc/defs.hh
index 858f49d..cf62992 100644
--- a/inc/defs.hh
+++ b/inc/defs.hh
@@ -1,10 +1,8 @@
 #pragma once
 
 #include <cstdint>
+#include <cstdlib>
 #include <cstring>
-#if defined(__x86_64__)
-#include <immintrin.h>
-#endif
 #include <ctime>
 #include <cstdio>
 #include <sys/types.h>
@@ -35,7 +33,7 @@ cmask_get_next_cpu(uint64_t *mask)
 static inline int
 cmask_get_num_cpus(const uint64_t mask)
 {
-	return _mm_popcnt_u64(mask);
+	return __builtin_popcount(mask);
 }
 #endif