Disable aligned new/delete on Apple platforms without posix_memalign

Summary:
This patch disables the aligned new/delet overloads on Apple platforms without `posix_memalign`. This fixes libc++.dylib build regressions on such platforms.
This fixes http://llvm.org/PR31448.

This patch should also be merged into the 4.0 release branch


Reviewers: mclow.lists, rsmith, dexonsmith, jeremyhu

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28931

llvm-svn: 292564
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: efea04512c28e1b8dea3d732e18a9213f3ed33c6
diff --git a/include/__config b/include/__config
index f214c7b..63f477b 100644
--- a/include/__config
+++ b/include/__config
@@ -848,6 +848,18 @@
 #define _DECLARE_C99_LDBL_MATH 1
 #endif
 
+#if defined(__APPLE__)
+# if !defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && \
+     defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#   define __MAC_OS_X_VERSION_MIN_REQUIRED __ENVIROMENT_MAC_OS_X_VERSION_MIN_REQUIRED__
+# endif
+# if defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
+#   if __MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+#     define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#   endif
+# endif
+#endif // defined(__APPLE__)
+
 #if defined(__APPLE__) || defined(__FreeBSD__)
 #define _LIBCPP_HAS_DEFAULTRUNELOCALE
 #endif
diff --git a/include/new b/include/new
index 6589f16..6e43501 100644
--- a/include/new
+++ b/include/new
@@ -101,8 +101,9 @@
 # define _LIBCPP_HAS_NO_SIZED_DEALLOCATION
 #endif
 
-#if !(defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER > 14 || \
-    (defined(__cpp_aligned_new) && __cpp_aligned_new >= 201606))
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) && \
+    (!(defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER > 14 || \
+    (defined(__cpp_aligned_new) && __cpp_aligned_new >= 201606)))
 # define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
 #endif
 
diff --git a/src/new.cpp b/src/new.cpp
index 391718f..b1e8ee3 100644
--- a/src/new.cpp
+++ b/src/new.cpp
@@ -151,6 +151,8 @@
     ::operator delete[](ptr);
 }
 
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+
 _LIBCPP_WEAK
 void *
 operator new(std::size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC
@@ -275,6 +277,8 @@
     ::operator delete[](ptr, alignment);
 }
 
+#endif // !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+
 #endif // !__GLIBCXX__
 
 namespace std