diff -durN gcc-4.4.5.orig/gcc/c-common.c gcc-4.4.5/gcc/c-common.c

--- gcc-4.4.5.orig/gcc/c-common.c	2010-07-27 15:07:28.000000000 +0200

+++ gcc-4.4.5/gcc/c-common.c	2010-10-09 22:59:03.000000000 +0200

@@ -301,7 +301,7 @@

 /* Warn about format/argument anomalies in calls to formatted I/O functions

    (*printf, *scanf, strftime, strfmon, etc.).  */

-int warn_format;

+int warn_format = 1;

 /* Warn about using __null (as NULL in C++) as sentinel.  For code compiled

    with GCC this doesn't matter as __null is guaranteed to have the right

diff -durN gcc-4.4.5.orig/gcc/c.opt gcc-4.4.5/gcc/c.opt

--- gcc-4.4.5.orig/gcc/c.opt	2009-09-18 23:53:23.000000000 +0200

+++ gcc-4.4.5/gcc/c.opt	2010-10-09 22:59:03.000000000 +0200

@@ -236,7 +236,7 @@

 Warn about format strings that contain NUL bytes

 Wformat-security

-C ObjC C++ ObjC++ Var(warn_format_security) Warning

+C ObjC C++ ObjC++ Var(warn_format_security) Init(1) Warning

 Warn about possible security problems with format functions

 Wformat-y2k

diff -durN gcc-4.4.5.orig/gcc/doc/invoke.texi gcc-4.4.5/gcc/doc/invoke.texi

--- gcc-4.4.5.orig/gcc/doc/invoke.texi	2010-09-08 20:13:03.000000000 +0200

+++ gcc-4.4.5/gcc/doc/invoke.texi	2010-10-09 22:59:03.000000000 +0200

@@ -2888,6 +2888,9 @@

 @option{-Wformat-nonliteral}, @option{-Wformat-security}, and

 @option{-Wformat=2} are available, but are not included in @option{-Wall}.

+NOTE: In Gentoo, this option is enabled by default for C, C++, ObjC, ObjC++.

+To disable, use @option{-Wformat=0}.

+

 @item -Wformat-y2k

 @opindex Wformat-y2k

 @opindex Wno-format-y2k

@@ -2941,6 +2944,11 @@

 in future warnings may be added to @option{-Wformat-security} that are not

 included in @option{-Wformat-nonliteral}.)

+NOTE: In Gentoo, this option is enabled by default for C, C++, ObjC, ObjC++.

+To disable, use @option{-Wno-format-security}, or disable all format warnings

+with @option{-Wformat=0}.  To make format security warnings fatal, specify

+@option{-Werror=format-security}.

+

 @item -Wformat=2

 @opindex Wformat=2

 @opindex Wno-format=2