From bc7cc576072703e4521844b949af5ce7d7e4722a Mon Sep 17 00:00:00 2001
From: fanquake <fanquake@gmail.com>
Date: Fri, 18 Feb 2022 15:53:18 +0000
Subject: [PATCH] doc: explain why we clear CXXFLAGS with enable-debug

---
 configure.ac | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 658b14180a2..82497c57a13 100644
--- a/configure.ac
+++ b/configure.ac
@@ -361,7 +361,9 @@ case $host in
 esac
 
 if test "$enable_debug" = "yes"; then
-  dnl Clear default -g -O2 flags
+  dnl If debugging is enabled, and the user hasn't overriden CXXFLAGS, clear
+  dnl them, to prevent autoconfs "-g -O2" being added. Otherwise we'd end up
+  dnl with "-O0 -g3 -g -O2".
   if test "$CXXFLAGS_overridden" = "no"; then
   CXXFLAGS=""
   fi