Merged in autoconf branch.  This provides configuration via the autoconf
system.

llvm-svn: 7014
diff --git a/llvm/lib/CodeGen/InstrSelection/InstrForest.cpp b/llvm/lib/CodeGen/InstrSelection/InstrForest.cpp
index ea2ccad..ceaefd8 100644
--- a/llvm/lib/CodeGen/InstrSelection/InstrForest.cpp
+++ b/llvm/lib/CodeGen/InstrSelection/InstrForest.cpp
@@ -21,6 +21,7 @@
 #include "llvm/Type.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "Support/STLExtras.h"
+#include "Config/alloca.h"
 
 //------------------------------------------------------------------------ 
 // class InstrTreeNode