Fix a file overwrite bug in llvm-ar introduced by changes to
createTemporaryFile semantics where it doesn't create a fully unique name
if the basename doesn't exist. This functionality is now optionally
provided by the boolean reuse_current parameter to createTemporaryFile and
makeUnique. The default values differ because of the way these functions
are used in LLVM.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18961 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/Path.cpp b/lib/System/Unix/Path.cpp
index d4bf026..84c2d2d 100644
--- a/lib/System/Unix/Path.cpp
+++ b/lib/System/Unix/Path.cpp
@@ -481,13 +481,13 @@
 }
 
 bool
-Path::createTemporaryFile() {
+Path::createTemporaryFile(bool reuse_current) {
   // Make sure we're dealing with a file
   if (!isFile()) 
     return false;
 
   // Make this into a unique file name
-  makeUnique();
+  makeUnique( reuse_current );
 
   // create the file
   int outFile = ::open(path.c_str(), O_WRONLY|O_CREAT|O_TRUNC, 0666);
@@ -600,8 +600,8 @@
 }
 
 void 
-Path::makeUnique() {
-  if (!exists())
+Path::makeUnique(bool reuse_current) {
+  if (reuse_current && !exists())
     return; // File doesn't exist already, just use it!
 
   // Append an XXXXXX pattern to the end of the file for use with mkstemp,