diff --git a/headers/private/kernel/real_time_clock.h b/headers/private/kernel/real_time_clock.h
index f7a2559f02..02aa0bdc39 100644
--- a/headers/private/kernel/real_time_clock.h
+++ b/headers/private/kernel/real_time_clock.h
@@ -17,10 +17,11 @@ status_t rtc_init(kernel_args *args);
 bigtime_t rtc_system_time_offset(void);
 	// Returns the time at which the system was booted in microseconds since Jan 1, 1970 (local or GMT).
 
+bigtime_t _user_system_time(void);
 status_t _user_set_real_time_clock(uint32 time);
-status_t _user_set_tzspecs(int32 timezone_offset, bool dst_observed);
-status_t _user_set_tzfilename(const char* filename, size_t length, bool is_gmt);
-status_t _user_get_tzfilename(char *filename, size_t length, bool *is_gmt);
+status_t _user_set_timezone(int32 timezoneOffset, bool daylightSavingTime);
+status_t _user_set_tzfilename(const char* filename, size_t length, bool isGMT);
+status_t _user_get_tzfilename(char *filename, size_t length, bool *_isGMT);
 
 #ifdef __cplusplus
 }
diff --git a/headers/private/kernel/syscalls.h b/headers/private/kernel/syscalls.h
index 81f58f08cf..e75a28b7b4 100644
--- a/headers/private/kernel/syscalls.h
+++ b/headers/private/kernel/syscalls.h
@@ -186,9 +186,9 @@ extern status_t		_kern_stop_watching(dev_t device, ino_t node, uint32 flags,
 
 // time functions
 extern status_t		_kern_set_real_time_clock(uint32 time);
-extern status_t		_kern_set_tzspecs(int32 timezone_offset, bool dst_observed);
-extern status_t		_kern_set_tzfilename(const char *filename, size_t length, bool is_gmt);
-extern status_t		_kern_get_tzfilename(char *filename, size_t length, bool *is_gmt);
+extern status_t		_kern_set_timezone(int32 timezoneOffset, bool daylightSavingTime);
+extern status_t		_kern_set_tzfilename(const char *filename, size_t length, bool isGMT);
+extern status_t		_kern_get_tzfilename(char *filename, size_t length, bool *_isGMT);
 
 extern bigtime_t	_kern_system_time();
 extern status_t		_kern_snooze_etc(bigtime_t time, int timebase, int32 flags);