doc: document config.h inclusion by flex itself

diff --git a/NEWS b/NEWS
index 4d98cb71388d8f48641f73f4ce1dd9a05b7a328a..89d5e7be5b7c5d166ff4f3964d0ca5d16e21eb82 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,11 @@ flex NEWS
 
 ** build
 
+*** Flex now includes its own <config.h> header before including
+    system headers so that any system specific features detected by
+    configure are taken into account during compilation of flex
+    itself.
+
 *** The flex build system now includes Makefile targets at the top
     level to allow just building and installing libfl.