diff --git a/include/debug.h b/include/debug.h
index 99383a3..c468d15 100644
--- a/include/debug.h
+++ b/include/debug.h
@@ -21,6 +21,9 @@
 #include <br.h>
 #include <bits.h>
 
+#define NANOSEC  1000000000                       /* nano sec in sec */
+#define MILLISEC 1000000                          /* milli sec in sec */
+
 #define _printf __attribute__ ((format (printf, 6, 7)))
 
 #ifdef DEBUG_DEBUG
@@ -29,6 +32,7 @@ void debug_init(uint level, FILE *stream, bool flush);
 void debug_level_set(uint level);
 uint debug_level_get(void);
 void debug_stream_set(FILE *stream);
+long long debug_timer_elapsed(void);
 void debug_flush_set(bool flush);
 void _printf debug(uint level, bool timestamp,
                    uint indent, const char *src,
@@ -41,6 +45,7 @@ static inline void debug_init(__unused uint level,
 static inline void debug_level_set(__unused uint level) {}
 static inline uint debug_level_get(void) {return 0;}
 static inline void debug_stream_set(__unused FILE *stream) {}
+static inline long long debug_timer_elapsed(void) {return 0LL};
 static inline void debug_flush_set(__unused bool level) {}
 static inline void _printf debug(__unused uint level, __unused bool timestamp,
                                  __unused uint indent, __unused const char *src,
diff --git a/libsrc/debug.c b/libsrc/debug.c
index 5d776cb..1ce280b 100644
--- a/libsrc/debug.c
+++ b/libsrc/debug.c
@@ -22,9 +22,6 @@
 #include "bits.h"
 #include "debug.h"
 
-#define NANOSEC  1000000000                       /* nano sec in sec */
-#define MILLISEC 1000000                          /* milli sec in sec */
-
 static long long timer_start;                     /* in nanosecond */
 static uint debug_level = 0;
 static bool debug_flush = false;
@@ -83,7 +80,7 @@ void debug_init(uint level, FILE *_stream, bool flush)
     log(0, "timer started.\n");
 }
 
-inline static long long timer_elapsed()
+long long debug_timer_elapsed(void)
 {
     struct timespec timer;
 
@@ -111,7 +108,7 @@ void debug(uint level, bool timestamp, uint indent, const char *src,
         fprintf(stream, "%*s", 2*(indent-1), "");
 
     if (timestamp) {
-        long long diff = timer_elapsed();
+        long long diff = debug_timer_elapsed();
         fprintf(stream, "%lld.%03lld ", diff/NANOSEC, (diff/1000000)%1000);
         fprintf(stream, "%010lld ", diff);
     }