diff --git a/winsup/cygwin/fhandler_random.cc b/winsup/cygwin/fhandler_random.cc
index c56ce73d3..1a3edd16f 100644
--- a/winsup/cygwin/fhandler_random.cc
+++ b/winsup/cygwin/fhandler_random.cc
@@ -7,6 +7,7 @@ Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
 details. */
 
 #include "winsup.h"
+#include <ntsecapi.h>
 #include <unistd.h>
 #include <sys/param.h>
 #include "cygerrno.h"
diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc
index 801a731a5..f3d1d6925 100644
--- a/winsup/cygwin/fhandler_socket.cc
+++ b/winsup/cygwin/fhandler_socket.cc
@@ -21,6 +21,7 @@
 #undef u_long
 #define u_long __ms_u_long
 #endif
+#include <ntsecapi.h>
 #include <ws2tcpip.h>
 #include <mswsock.h>
 #include <iphlpapi.h>
diff --git a/winsup/cygwin/miscfuncs.cc b/winsup/cygwin/miscfuncs.cc
index 0b19b2892..e92ccbabb 100644
--- a/winsup/cygwin/miscfuncs.cc
+++ b/winsup/cygwin/miscfuncs.cc
@@ -8,6 +8,7 @@ details. */
 
 #include "winsup.h"
 #include "miscfuncs.h"
+#include <ntsecapi.h>
 #include <sys/uio.h>
 #include <assert.h>
 #include <alloca.h>
diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
index bf5a7cf80..448eadf20 100644
--- a/winsup/cygwin/ntdll.h
+++ b/winsup/cygwin/ntdll.h
@@ -1608,10 +1608,4 @@ extern "C"
 
   }
 }
-
-/* There's a bug in ntsecapi.h (Mingw as well as MSFT).  SystemFunction036
-   is, in fact, a WINAPI function, but it's not defined as such.  Therefore
-   we have to do it correctly here.  *Strictly*, this is not ntdll... */
-#define RtlGenRandom SystemFunction036
-extern "C" BOOLEAN WINAPI RtlGenRandom (PVOID, ULONG);
 #endif
diff --git a/winsup/cygwin/ntsecapi.h b/winsup/cygwin/ntsecapi.h
new file mode 100644
index 000000000..8b0a7e77f
--- /dev/null
+++ b/winsup/cygwin/ntsecapi.h
@@ -0,0 +1,26 @@
+#ifndef _CYGWIN_NTSECAPI_H
+#define _CYGWIN_NTSECAPI_H
+
+/* There's a bug in ntsecapi.h (Mingw as well as MSFT).  SystemFunction036
+   is, in fact, a WINAPI function, but it's not defined as such.  Therefore
+   we have to do it correctly here in the ntsecapi.h wrapper. */
+
+#define SystemFunction036	__nonexistant_SystemFunction036__
+
+#include_next <ntsecapi.h>
+
+#undef SystemFunction036
+
+#define RtlGenRandom SystemFunction036
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+BOOLEAN WINAPI RtlGenRandom (PVOID, ULONG);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* _CYGWIN_NTSECAPI_H */