Define RtlGenRandom correctly in ntsecapi.h wrapper

Include ntsecapi.h where required and just redefine RtlGenRandom
correctly in the ntsecapi.h wrapper.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

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 */