[gcc r13-2752] libstdc++: Add _Exit to <stdlib.h> for freestanding

[Jonathan Wakely]

https://gcc.gnu.org/g:cb29396e67f5e2622e31bf83f253c6d66c51135d

commit r13-2752-gcb29396e67f5e2622e31bf83f253c6d66c51135d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Sep 21 00:48:12 2022 +0100

    libstdc++: Add _Exit to <stdlib.h> for freestanding
    
    When I added std::_Exit to the freestanding declarations in <cstdlib> I
    should also have added it to <stdlib.h>.
    
    libstdc++-v3/ChangeLog:
    
            * include/c_compatibility/stdlib.h [!_GLIBCXX_HOSTED]: Add
            using-declaration for _Exit.

Diff:
---
 libstdc++-v3/include/c_compatibility/stdlib.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libstdc++-v3/include/c_compatibility/stdlib.h b/libstdc++-v3/include/c_compatibility/stdlib.h
index 377b9107ded..70fa4c8e503 100644
--- a/libstdc++-v3/include/c_compatibility/stdlib.h
+++ b/libstdc++-v3/include/c_compatibility/stdlib.h
@@ -45,6 +45,9 @@ using std::exit;
 # ifdef _GLIBCXX_HAVE_QUICK_EXIT
   using std::quick_exit;
 # endif
+# if _GLIBCXX_USE_C99_STDLIB
+  using std::_Exit;
+# endif
 #endif
 
 #if _GLIBCXX_HOSTED