Make VCRuntime ABI configuration a first-class option.

Summary:
On Windows we currently provide two separate ABI configurations. One which defers to `vcruntime` to provide the C++ runtime and another which doesn't.
Using `vcruntime` allows interoperability which programs compiled against the MSVC STL, and should be preferred whenever possible.

When deferring to `vcruntime` much of the ABI we provide changes. Including the layout of `<stdexcept>` types, their vtables, and how the linkage of their members.

This patch introduces the `_LIBCPP_ABI_VCRUNTIME` macro to denote this configuration. It also cleans up the existing configuration for using `vcruntime`.

This cleanup lays the groundwork for fixing a number of ABI and interoperability bugs in  `<stdexcept>`.


Reviewers: thomasanderson, ldionne, smeenai

Reviewed By: smeenai

Subscribers: jdoerfert, libcxx-commits, #libc

Differential Revision: https://reviews.llvm.org/D58942

llvm-svn: 355366
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e69290dc7ff7319acf5904f15ab6630fad07ab58
diff --git a/src/new.cpp b/src/new.cpp
index 4acb693..eb629b3 100644
--- a/src/new.cpp
+++ b/src/new.cpp
@@ -12,7 +12,7 @@
 #include "include/atomic_support.h"
 
 #if defined(_LIBCPP_ABI_MICROSOFT)
-#if defined(_LIBCPP_NO_VCRUNTIME)
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
 #include "support/runtime/new_handler_fallback.ipp"
 #endif
 #elif defined(LIBCXX_BUILDING_LIBCXXABI)
@@ -54,7 +54,7 @@
 }  // std
 
 #if !defined(__GLIBCXX__) &&                                                   \
-    !defined(_LIBCPP_DEFER_NEW_TO_VCRUNTIME) &&      \
+    !defined(_LIBCPP_ABI_VCRUNTIME) &&      \
     !defined(_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
 
 // Implement all new and delete operators as weak definitions
@@ -298,4 +298,4 @@
 }
 
 #endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-#endif // !__GLIBCXX__ && (!_LIBCPP_ABI_MICROSOFT || _LIBCPP_NO_VCRUNTIME) && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS
+#endif // !__GLIBCXX__ && !_LIBCPP_ABI_VCRUNTIME && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS