Add back #include of 'cstdio' to hopefully unbreak the build on Linux.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@92765 91177308-0d34-0410-b5e6-96231b3b80d8

tools/CIndex/CIndex.cpp

@@ -19,6 +19,9 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/System/Program.h"
 
+// Needed to define L_TMPNAM on some systems.
+#include <cstdio>
+
 using namespace clang;
 using namespace idx;