[PATCH 1 of 5] scripts/libc: do not build add-ons by default

[BenoÃt THÃBAUDEAU <benoit dot thebaudeau at advansee dot com>]

# HG changeset patch
# User "BenoÃt THÃBAUDEAU" <benoit.thebaudeau@advansee.com>
# Date 1311766042 -7200
# Node ID 0ee44cad2124dcf96979819f0ee4851dd6ef2334
# Parent  2651341cc084a0b6e5858f666c8a851fa6cbfa92
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.

diff --git a/scripts/build/libc/glibc-eglibc.sh-common b/scripts/build/libc/glibc-eglibc.sh-common
--- a/scripts/build/libc/glibc-eglibc.sh-common
+++ b/scripts/build/libc/glibc-eglibc.sh-common
@@ -142,7 +142,7 @@
     fi
 
     case "$(do_libc_add_ons_list ,)" in
-        "") ;;
+        "") extra_config+=("--enable-add-ons=no");;
         *)  extra_config+=("--enable-add-ons=$(do_libc_add_ons_list ,)");;
     esac