[libcxx][NFC] Properly indent nested #ifdefs and #defines

I just realized I had always been reading this wrong because of the lack
of indentation, so I'm re-indenting this properly.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@349408 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__config b/include/__config
index b5e7b76..7283876 100644
--- a/include/__config
+++ b/include/__config
@@ -977,14 +977,14 @@
 // If we are getting operator new from the MSVC CRT, then allocation overloads
 // for align_val_t were added in 19.12, aka VS 2017 version 15.3.
 #if defined(_LIBCPP_MSVCRT) && defined(_MSC_VER) && _MSC_VER < 1912
-#define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#  define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
 #elif defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
-#define _LIBCPP_DEFER_NEW_TO_VCRUNTIME
-#if !defined(__cpp_aligned_new)
-// We're defering to Microsoft's STL to provide aligned new et al. We don't
-// have it unless the language feature test macro is defined.
-#define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-#endif
+#  define _LIBCPP_DEFER_NEW_TO_VCRUNTIME
+#  if !defined(__cpp_aligned_new)
+     // We're defering to Microsoft's STL to provide aligned new et al. We don't
+     // have it unless the language feature test macro is defined.
+#    define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#  endif
 #endif
 
 #if defined(__APPLE__)