diff --git a/CMakeLists.txt b/CMakeLists.txt
index d39672e..1d00d5c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -151,6 +151,7 @@ check_include_file("sys/types.h"   HAVE_SYS_TYPES_H)
 check_function_exists(gettimeofday    LIBVNCSERVER_HAVE_GETTIMEOFDAY)
 check_function_exists(vfork           LIBVNCSERVER_HAVE_VFORK)
 check_function_exists(vprintf         LIBVNCSERVER_HAVE_VPRINTF)
+check_function_exists(mmap            LIBVNCSERVER_HAVE_MMAP)
 
 
 # On systems such as GNU/Linux with glibc, __b64_ntop is defined in a
diff --git a/rfb/rfbconfig.h.cmake b/rfb/rfbconfig.h.cmake
index 86f7ae3..661583d 100644
--- a/rfb/rfbconfig.h.cmake
+++ b/rfb/rfbconfig.h.cmake
@@ -72,6 +72,9 @@
 /* Define to 1 if `vfork' works. */
 #cmakedefine LIBVNCSERVER_HAVE_WORKING_VFORK  1 
 
+/* Define to 1 if `mmap' exists. */
+#cmakedefine LIBVNCSERVER_HAVE_MMAP  1 
+
 /* Define to 1 if you have the <ws2tcpip.h> header file. */
 #cmakedefine LIBVNCSERVER_HAVE_WS2TCPIP_H  1