From: Tony Finch <fanf@isc.org>
Date: Wed, 15 Feb 2023 19:00:37 +0000 (+0000)
Subject: Avoid redefining _FORTIFY_SOURCE
X-Git-Tag: v9.19.11~58^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b0377f798f6794b6c93be150da6bc3fc140f1ce4;p=thirdparty%2Fbind9.git

Avoid redefining _FORTIFY_SOURCE

Some compilers have a built-in definition of the _FORTIFY_SOURCE macro
that differs from BIND's preferred setting. This causes errors like
the one quoted below. The solution is to undefine the macro before
defining it. A similar fix was recently committed to glibc.

    <command line>: error: '_FORTIFY_SOURCE' macro redefined
    #define _FORTIFY_SOURCE 2
            ^
    <built-in>: note: previous definition is here
    #define _FORTIFY_SOURCE 0
	    ^

https://sourceware.org/git/glibc.git/commitdiff/35bcb08eaa953c9b
---

diff --git a/configure.ac b/configure.ac
index 4aa1761b26d..c180364dfb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -134,8 +134,9 @@ STD_LDFLAGS=""
 # ... except in test code
 TEST_CFLAGS="-Wno-vla"
 
-# Fortify the sources by default
-STD_CPPFLAGS="-D_FORTIFY_SOURCE=2"
+# Fortify the sources by default (we undefine the macro first in case
+# the compiler has a different built-in setting)
+STD_CPPFLAGS="-U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2"
 
 #
 # Additional compiler settings.