diff --git a/cmake/Libraries.cmake b/cmake/Libraries.cmake
index 61da376be..2698f4ef3 100644
--- a/cmake/Libraries.cmake
+++ b/cmake/Libraries.cmake
@@ -83,7 +83,12 @@ macro(configure_unix_libs)
   include(CheckCSourceCompiles)
 
   check_include_files(sys/socket.h HAVE_SYS_SOCKET_H)
+
+
   check_include_files(unistd.h HAVE_UNISTD_H)
+  if (NOT HAVE_UNISTD_H)
+    message(FATAL_ERROR "Missing unistd.h")
+  endif()
 
   check_function_exists(sigwait HAVE_POSIX_SIGWAIT)
   check_function_exists(inet_aton HAVE_INET_ATON)
diff --git a/src/lib/Config.h.in b/src/lib/Config.h.in
index 0b93f3f58..7ed0acf0d 100644
--- a/src/lib/Config.h.in
+++ b/src/lib/Config.h.in
@@ -31,9 +31,6 @@
 /* Define to 1 if you have the <sys/types.h> header file. */
 #cmakedefine HAVE_SYS_TYPES_H @HAVE_SYS_TYPES_H@
 
-/* Define to 1 if you have the <unistd.h> header file. */
-#cmakedefine HAVE_UNISTD_H @HAVE_UNISTD_H@
-
 /* Define to 1 if you have the <X11/extensions/Xrandr.h> header file. */
 #cmakedefine HAVE_X11_EXTENSIONS_XRANDR_H @HAVE_X11_EXTENSIONS_XRANDR_H@
 
diff --git a/src/lib/arch/unix/ArchNetworkBSD.cpp b/src/lib/arch/unix/ArchNetworkBSD.cpp
index f08632d4d..a450bd115 100644
--- a/src/lib/arch/unix/ArchNetworkBSD.cpp
+++ b/src/lib/arch/unix/ArchNetworkBSD.cpp
@@ -18,10 +18,7 @@
 #include <fcntl.h>
 #include <netdb.h>
 #include <netinet/in.h>
-
-#if HAVE_UNISTD_H
 #include <unistd.h>
-#endif
 
 #if !defined(TCP_NODELAY)
 #include <netinet/tcp.h>
diff --git a/src/lib/platform/XWindowsEventQueueBuffer.cpp b/src/lib/platform/XWindowsEventQueueBuffer.cpp
index 36732c7c9..23111572b 100644
--- a/src/lib/platform/XWindowsEventQueueBuffer.cpp
+++ b/src/lib/platform/XWindowsEventQueueBuffer.cpp
@@ -13,11 +13,8 @@
 #include "mt/Thread.h"
 
 #include <fcntl.h>
-#if HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
 #include <poll.h>
+#include <unistd.h>
 
 //
 // EventQueueTimer