scripts/libc: do not build add-ons by default

Currently, no --enable-add-ons option is passed to libc configure when
"$(do_libc_add_ons_list ,)" is empty, which makes configure automatically search
for present add-ons. In that case, all present add-ons are built, although
no add-on was selected by the user in the config. Moreover, this can make the
configure fail if some non-standard add-ons like eglibc-localedef are present.

This behavior also leads to an inconsistency from a user point of view between
the following cases:
- LIBC_ADDONS_LIST="", LIBC_GLIBC_USE_PORTS=n and THREADS="none" in the config,
which makes "$(do_libc_add_ons_list ,)" return "", so all present add-ons
are built.
- LIBC_ADDONS_LIST="", LIBC_GLIBC_USE_PORTS=n and THREADS!="none" in the
config, which makes "$(do_libc_add_ons_list ,)" return the add-on supporting
the chosen threading implementation, e.g. "nptl", so only this add-on is
built.

This patch disables the building of all add-ons in that case.

It is still possible to build all present add-ons by adding --enable-add-ons to
LIBC_GLIBC_EXTRA_CONFIG_ARRAY.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

ripped from SuSE

if /etc/resolv.conf is updated, then make sure applications

already running get the updated information.

http://bugs.gentoo.org/177416

diff -durN glibc-2.12.1.orig/resolv/res_libc.c glibc-2.12.1/resolv/res_libc.c

--- glibc-2.12.1.orig/resolv/res_libc.c	2009-02-07 05:27:42.000000000 +0100

+++ glibc-2.12.1/resolv/res_libc.c	2009-11-13 00:49:59.000000000 +0100

@@ -22,6 +22,7 @@

 #include <arpa/nameser.h>

 #include <resolv.h>

 #include <bits/libc-lock.h>

+#include <sys/stat.h>

 /* The following bit is copied from res_data.c (where it is #ifdef'ed

@@ -95,6 +96,20 @@

 __res_maybe_init (res_state resp, int preinit)

 {

 	if (resp->options & RES_INIT) {

+		static time_t last_mtime, last_check;

+		time_t now;

+		struct stat statbuf;

+		

+		time (&now);

+		if (now != last_check) {

+			last_check = now;

+			if (stat (_PATH_RESCONF, &statbuf) == 0 && last_mtime != statbuf.st_mtime) {

+				last_mtime = statbuf.st_mtime;

+				atomicinclock (lock);

+				atomicinc (__res_initstamp);

+				atomicincunlock (lock);

+			}

+		}

 		if (__res_initstamp != resp->_u._ext.initstamp) {

 			if (resp->nscount > 0)

 				__res_iclose (resp, true);