diff --git a/include/villas/rdtsc.h b/include/villas/rdtsc.h
index bda3c1599..c9b38ff4c 100644
--- a/include/villas/rdtsc.h
+++ b/include/villas/rdtsc.h
@@ -25,6 +25,7 @@
 
 #include <stdint.h>
 #include <cpuid.h>
+#include <inttypes.h>
 
 #include <stdio.h>
 
@@ -33,6 +34,11 @@
   #include <sys/sysctl.h>
 #endif
 
+
+#ifndef bit_TSC
+  #define bit_TSC (1 << 4)
+#endif
+
 #define bit_TSC_INVARIANT	(1 << 8)
 #define bit_RDTSCP		(1 << 27)
 
@@ -56,7 +62,8 @@ static inline uint64_t rdtscp()
 	return tsc;
 }
 
-int rdtsc_init(uint64_t *freq)
+static int rdtsc_init(uint64_t *freq) __attribute__((unused));
+static int rdtsc_init(uint64_t *freq)
 {
 	uint32_t eax, ebx, ecx, edx;
 
@@ -89,7 +96,7 @@ int rdtsc_init(uint64_t *freq)
 		if (!f)
 			return -1;
 
-		ret = fscanf(f, "%d", freq);
+		ret = fscanf(f, "%" PRIu64, freq);
 
 		fclose(f);
 
diff --git a/tests/unit/queue.c b/tests/unit/queue.c
index d33f82d5c..25a5210de 100644
--- a/tests/unit/queue.c
+++ b/tests/unit/queue.c
@@ -34,6 +34,7 @@
 #include <villas/utils.h>
 #include <villas/queue.h>
 #include <villas/memory.h>
+#include <villas/rdtsc.h>
 
 #define SIZE	(1 << 10)