diff --git a/configure.ac b/configure.ac
index 9cec626..78f8c24 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,10 +6,14 @@ AM_INIT_AUTOMAKE([foreign std-options subdir-objects])
 
 # Check for programs.
 AC_PROG_CC
+AC_PROG_CC_C99
 AC_PROG_INSTALL
 AC_PROG_RANLIB
 PKG_PROG_PKG_CONFIG
 
+# Enable POSIX
+AC_DEFINE([_POSIX_C_SOURCE], [200809L], [Use POSIX 2008 features])
+
 # Check for header files.
 AC_CHECK_HEADERS(
   [limits.h sys/time.h sys/types.h sys/stat.h dirent.h unistd.h fnmatch.h ncurses.h],[],
@@ -25,7 +29,7 @@ AC_STRUCT_ST_BLOCKS
 
 # Check for library functions.
 AC_CHECK_FUNCS(
-  [getcwd gettimeofday fnmatch chdir rmdir unlink lstat system getenv],[],
+  [getcwd clock_gettime fnmatch chdir rmdir unlink lstat system getenv],[],
   AC_MSG_ERROR([required function missing]))
 
 AC_CHECK_FUNCS(statfs)
diff --git a/src/main.c b/src/main.c
index 13b6de8..4dfe4be 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,7 +31,7 @@
 #include <errno.h>
 
 #include <unistd.h>
-#include <sys/time.h>
+#include <time.h>
 
 #include <yopt.h>
 
@@ -48,7 +48,7 @@ int confirm_quit = 0;
 static int min_rows = 17, min_cols = 60;
 static int ncurses_init = 0;
 static int ncurses_tty = 0; /* Explicitely open /dev/tty instead of using stdio */
-static long lastupdate = 999;
+static long lastupdate = 999999;
 
 
 static void screen_draw(void) {
@@ -70,16 +70,16 @@ static void screen_draw(void) {
  */
 int input_handle(int wait) {
   int ch;
-  struct timeval tv;
+  struct timespec ts;
 
   if(wait != 1)
     screen_draw();
   else {
-    gettimeofday(&tv, NULL);
-    tv.tv_usec = (1000*(tv.tv_sec % 1000) + (tv.tv_usec / 1000)) / update_delay;
-    if(lastupdate != tv.tv_usec) {
+    clock_gettime(CLOCK_REALTIME, &ts);
+    ts.tv_nsec = (1000000*(ts.tv_sec % 1000) + (ts.tv_nsec / 1000)) / update_delay;
+    if(lastupdate != ts.tv_nsec) {
       screen_draw();
-      lastupdate = tv.tv_usec;
+      lastupdate = ts.tv_nsec;
     }
   }
 
diff --git a/src/util.c b/src/util.c
index 8448956..48df7bb 100644
--- a/src/util.c
+++ b/src/util.c
@@ -124,14 +124,13 @@ char *fullsize(int64_t from) {
 
 char *fmtmode(unsigned short mode) {
   static char buf[11];
-  unsigned short ft = mode & S_IFMT;
-  buf[0] = ft == S_IFDIR  ? 'd'
-         : ft == S_IFREG  ? '-'
-         : ft == S_IFLNK  ? 'l'
-         : ft == S_IFIFO  ? 'p'
-         : ft == S_IFSOCK ? 's'
-         : ft == S_IFCHR  ? 'c'
-         : ft == S_IFBLK  ? 'b' : '?';
+  buf[0] = S_ISDIR(mode)  ? 'd'
+         : S_ISREG(mode)  ? '-'
+         : S_ISLNK(mode)  ? 'l'
+         : S_ISFIFO(mode) ? 'p'
+         : S_ISSOCK(mode) ? 's'
+         : S_ISCHR(mode)  ? 'c'
+         : S_ISBLK(mode)  ? 'b' : '?';
   buf[1] = mode & 0400 ? 'r' : '-';
   buf[2] = mode & 0200 ? 'w' : '-';
   buf[3] = mode & 0100 ? 'x' : '-';