document the NORET macro

git-svn-id: https://svn.r-project.org/R/trunk@87418 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: ripley

config.site

@@ -90,6 +90,13 @@
 ## DEFS="-DC99_INLINE_SEMANTICS=0"
 ## DEFS=
 
+## no-return flag
+## Header R-exts/Error.h contains alternaive definitions for the NORET
+## macro, depending on the C standard found.  If the compiler does not
+## comply (and GCC pre=15 did not in 2024-12), use this to pick one of the
+## others, or even define to be empty.
+## NORET=
+
 ## The following additional CFLAGS to be used only in the main
 ## compilation and only in building shared objects respectively.
 ## For example, on some systems one needs 'MAIN_CFLAGS=-pg' when