From b13a74b35b17ecb44ec6ff552ecb1cbdac204361 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Thu, 18 Feb 2016 09:57:35 -0500
Subject: [PATCH 1/2] cmSystemTools: Remove unused include <fcntl.h>

We do not seem to need this header anymore, and including it on AIX
causes `#define open open64` which breaks `std::ifstream::open` calls.
---
 Source/cmSystemTools.cxx | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 3ba72876c3..c9670faf08 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -60,8 +60,7 @@
 #endif
 
 #if defined(CMAKE_BUILD_WITH_CMAKE)
-#  include <fcntl.h>
-#  include "cmCryptoHash.h"
+# include "cmCryptoHash.h"
 #endif
 
 #if defined(CMAKE_USE_ELF_PARSER)

From f23f18ab686faa0ce91486143469bb58753b0843 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cristian=20Rodr=C3=ADguez?= <crrodriguez@opensuse.org>
Date: Wed, 17 Feb 2016 09:02:04 -0500
Subject: [PATCH 2/2] cmSystemTools: Avoid excess entropy consumption by
 RandomSeed (#15976)

Read `/dev/urandom` without buffering to avoid taking more than we need.
---
 Source/cmSystemTools.cxx | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index c9670faf08..9af54bffca 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -2183,8 +2183,10 @@ unsigned int cmSystemTools::RandomSeed()
   } seed;
 
   // Try using a real random source.
-  cmsys::ifstream fin("/dev/urandom");
-  if(fin && fin.read(seed.bytes, sizeof(seed)) &&
+  cmsys::ifstream fin;
+  fin.rdbuf()->pubsetbuf(0, 0); // Unbuffered read.
+  fin.open("/dev/urandom");
+  if(fin.good() && fin.read(seed.bytes, sizeof(seed)) &&
      fin.gcount() == sizeof(seed))
     {
     return seed.integer;