Move atomic_support.h and config_elast.h into src/include

llvm-svn: 245354
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e8fd1645695e6920537731ae70b0ffb894df514c
diff --git a/src/ios.cpp b/src/ios.cpp
index 90972c4..9d9daa9 100644
--- a/src/ios.cpp
+++ b/src/ios.cpp
@@ -15,7 +15,7 @@
 
 #include "__locale"
 #include "algorithm"
-#include "config_elast.h"
+#include "include/config_elast.h"
 #include "istream"
 #include "limits"
 #include "memory"