diff --git a/protocols/vnc/configure.in b/protocols/vnc/configure.in
index 35d8c3fa..2080594c 100644
--- a/protocols/vnc/configure.in
+++ b/protocols/vnc/configure.in
@@ -18,6 +18,7 @@ AC_CHECK_LIB([vncclient], [rfbInitClient],, AC_MSG_ERROR("libvncclient is requir
 AC_CHECK_HEADERS([stdlib.h string.h syslog.h guacamole/client.h guacamole/guacio.h guacamole/protocol.h])
 
 # Checks for library functions.
+AC_CHECK_FUNCS([nanosleep])
 AC_FUNC_MALLOC
 
 AC_CONFIG_FILES([Makefile])
diff --git a/protocols/vnc/src/vnc_client.c b/protocols/vnc/src/vnc_client.c
index 6c374433..f66997cd 100644
--- a/protocols/vnc/src/vnc_client.c
+++ b/protocols/vnc/src/vnc_client.c
@@ -199,17 +199,17 @@ void guac_vnc_cut_text(rfbClient* client, const char* text, int textlen) {
 
 void vnc_guac_client_sleep(int millis) {
 
-#ifdef nanosleep
+#ifdef HAVE_NANOSLEEP 
         struct timespec sleep_period;
 
         sleep_period.tv_sec = 0;
         sleep_period.tv_nsec = millis * 1000000L;
 
         nanosleep(&sleep_period, NULL);
-#else
-#ifdef Sleep
+#elif defined(__MINGW32__)
         Sleep(millis)
-#endif
+#else
+#warning No sleep/nanosleep function available. VNC client may not perform as expected. Consider editing the vnc_client.c to add support for your platform.
 #endif
 
 }