[glibc] Define __THROW to noexcept for C++11 and later

[glibc] Define __THROW to noexcept for C++11 and later

[Jonathan Wakely]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d445d9ca8d961148ffde8ec597ecc0e050542024

commit d445d9ca8d961148ffde8ec597ecc0e050542024
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Sep 22 11:54:38 2020 +0100

    Define __THROW to noexcept for C++11 and later
    
    The __THROW macro and friends expand to "throw ()" for C++ code, but
    that syntax is deprecated in C++11 and no longer supported at all since
    C++20. In order for glibc headers to be compatible with C++20,
    "noexcept" should be used instead.
    
    This patch uses "noexcept (true)" rather than just "noexcept", which is
    semantically equivalent, but avoids any possibility of parsing
    ambiguities if the next preprocessor token happens to be an opening
    parenthesis. This is probably unnecessary, but it seems safer to be
    cautious.

Diff:
---
 misc/sys/cdefs.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 19d9cc5cfe..6b9763a92a 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -58,10 +58,14 @@
 #  define __NTHNL(fct)  __attribute__ ((__nothrow__)) fct
 # else
 #  if defined __cplusplus && __GNUC_PREREQ (2,8)
-#   define __THROW	throw ()
-#   define __THROWNL	throw ()
-#   define __NTH(fct)	__LEAF_ATTR fct throw ()
-#   define __NTHNL(fct) fct throw ()
+#   if __cplusplus >= 201103L
+#    define __THROW	noexcept (true)
+#   else
+#    define __THROW	throw ()
+#   endif
+#   define __THROWNL	__THROW
+#   define __NTH(fct)	__LEAF_ATTR fct __THROW
+#   define __NTHNL(fct) fct __THROW
 #  else
 #   define __THROW
 #   define __THROWNL