Merge pull request #255 from costashatz/fix_old_gcc_clang

Fix compilation (veg/memory) for gcc 7 and clang 7

Author: jcarpent

include/proxsuite/linalg/veg/memory/alloc.hpp

@@ -165,13 +165,13 @@ aligned_alloc(usize align, usize size) noexcept -> void*
 #if defined(_WIN32)
   return _aligned_malloc((size + mask) & ~mask, align);
 #elif defined(__APPLE__)
-#ifdef PROXSUITE_WITH_CPP_17
+#if defined(PROXSUITE_WITH_CPP_17) && defined(_LIBCPP_HAS_ALIGNED_ALLOC)
   return alignment::aligned_alloc(align, (size + mask) & ~mask);
 #else
   return alignment::detail::aligned_alloc(align, (size + mask) & ~mask);
 #endif
 #else
-#ifdef PROXSUITE_WITH_CPP_17
+#if defined(PROXSUITE_WITH_CPP_17) && defined(_LIBCPP_HAS_ALIGNED_ALLOC)
   return std::aligned_alloc(align, (size + mask) & ~mask);
 #else
   return alignment::detail::aligned_alloc(align, (size + mask) & ~mask);

include/proxsuite/linalg/veg/memory/placement.hpp

@@ -41,7 +41,7 @@
 
 #if VEG_HAS_BUILTIN(__builtin_launder) || __GNUC__ >= 7
 #define VEG_LAUNDER(p) (__builtin_launder(p))
-#elif defined(VEG_WITH_CXX17_SUPPORT)
+#elif defined(VEG_WITH_CXX17_SUPPORT) && __GNUC__ >= 6
 #include <new>
 #define VEG_LAUNDER(p) (::std::launder(p))
 #else