From 0412474323abf9c58bc87309993b4972282a9573 Mon Sep 17 00:00:00 2001
From: Erik <erikgreenwald@users.sourceforge.net>
Date: Tue, 30 Aug 2011 14:29:48 -0400
Subject: [PATCH] Cope with cross-device links (add simple copy)

---
 Source/cmSystemTools.cxx |   30 +++++++++++++++++++++++++++++-
 1 files changed, 29 insertions(+), 1 deletions(-)

diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 03364bd..602ddef 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -1190,7 +1190,35 @@ bool cmSystemTools::RenameFile(const char* oldname, const char* newname)
     }
 #else
   /* On UNIX we have an OS-provided call to do this atomically.  */
-  return rename(oldname, newname) == 0;
+  /* if the two files are on different devices, fall back to a manual copy */
+  if(rename(oldname, newname) == -1) 
+    {
+      if(errno == EXDEV)
+	{
+	char buf[BUFSIZ];
+	int s, in, out;
+	if((in = open(oldname, O_RDONLY|O_NONBLOCK)) == -1)
+	  return false;
+	if((out = open(newname, O_WRONLY|O_TRUNC|O_CREAT,0644)) == -1)
+	  {
+	  close(in);
+	  return false;
+	  }
+	while((s=read(in, buf, BUFSIZ))>=0)
+	  {
+	  if(s==-1 || s==0)
+	    {
+	    close(in);
+	    close(out);
+	    unlink(s==-1?newname:oldname);
+	    return s==0;
+	    }
+	  write(out, buf, s);
+	  }
+	}
+      return false;	/* rename() failed for something other than EXDEV */
+    }
+  return true;
 #endif
 }
 
-- 
1.7.3.4