document C23 changes

git-svn-id: https://svn.r-project.org/R/trunk@87376 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: ripley

doc/NEWS.Rd

@@ -391,7 +391,18 @@
 }
 
 \section{\Rlogo CHANGES IN R 4.4.2 patched}{
- \subsection{C-LEVEL FACILITIES}{
+  \subsection{INSTALLATION}{
+    \itemize{
+      \item \R can be installed using C23 (for example with
+      \option{-std=gnu23} or \option{-std=gnu2x}) with recent compilers
+      including \command{gcc} 14, Apple \command{clang} 16 and LLVM
+      \command{clang} 17--19.  (LLVM \command{clang} 18 and 19 objected
+      to apparently valid code using attributes accepted by all the
+      other compilers.)
+    }
+  }
+
+  \subsection{C-LEVEL FACILITIES}{
     \itemize{
       \item The functions \code{R_strtod} and \code{R_atof} now allow
       hexadecimal constants without an exponent, for compatibility with