libc/glibc: add fortify option

By default, recent versions of glibc and eglibc will build some
functions that take format strings (eg. printf, syslog...) with
run-time checks against some format string attacks. This is
called a fortified build.

Unfortunately, this fails somehow while building the instrumented
version of syslog, with some kind of circular dependency...

Disable fortified builds by default, and hide the enabling option
behind EXPERIMENTAL for daring users...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

diff -dur ELFkickers.orig/sstrip/Makefile ELFkickers/sstrip/Makefile

--- ELFkickers.orig/sstrip/Makefile	2001-03-24 12:58:27.000000000 +0100

+++ ELFkickers/sstrip/Makefile	2007-05-31 21:17:18.000000000 +0200

@@ -1,7 +1,7 @@

 #  Makefile for sstrip

 sstrip: sstrip.c

-	gcc -ggdb -Wall -W -o sstrip sstrip.c

+	$(CC) -Wall -W -o sstrip sstrip.c

 clean:

 	rm -f sstrip