libc/eglibc: fix localedef 2.14 build

The localedef of eglibc 2.14 requires NOT_IN_libc to be defined in order to
compile intl/l10nflist.c.

This is because localedef is built separately from eglibc and uses some parts of
eglibc that don't compile in standalone without this preprocessor definition.

This fixes the following error:

[ALL  ]    gcc  -g -O2 -DNO_SYSCONF -DNO_UNCOMPRESS
 -DLOCALE_PATH='"/usr/lib/locale:/usr/share/i18n"'
 -DLOCALEDIR='"/usr/lib/locale"' -DLOCALE_ALIAS_PATH='"/usr/share/locale"'
 -DCHARMAP_PATH='"/usr/share/i18n/charmaps"'
 -DREPERTOIREMAP_PATH='"/usr/share/i18n/repertoiremaps"'
 -DLOCSRCDIR='"/usr/share/i18n/locales"' -Iglibc/locale/programs -Iglibc/locale
 -I/<snip>/.build/src/eglibc-localedef-2_14/include
 -I/<snip>/.build/src/eglibc-localedef-2_14 -I.
 -include /<snip>/.build/src/eglibc-localedef-2_14/include/always.h -Wall
 -Wno-format -c -o locarchive.o glibc/locale/programs/locarchive.c
[ALL  ]    glibc/locale/programs/locarchive.c: In function 'enlarge_archive':
[ALL  ]    glibc/locale/programs/locarchive.c:303:21: warning: variable
 'oldlocrectab' set but not used [-Wunused-but-set-variable]
[ALL  ]    In file included from glibc/locale/programs/locarchive.c:651:0:
[ALL  ]    glibc/locale/programs/../../intl/l10nflist.c: In function
 '_nl_normalize_codeset':
[ERROR]    glibc/locale/programs/../../intl/l10nflist.c:342:9: error:
 '_nl_C_locobj_ptr' undeclared (first use in this function)
[ALL  ]    glibc/locale/programs/../../intl/l10nflist.c:342:9: note: each
 undeclared identifier is reported only once for each function it appears in
[ALL  ]    glibc/locale/programs/locarchive.c: In function
 'add_locales_to_archive':
[ALL  ]    glibc/locale/programs/locarchive.c:1450:7: warning: passing argument
 1 of '__xpg_basename' discards 'const' qualifier from pointer target type
 [enabled by default]
[ALL  ]    /usr/include/libgen.h:35:14: note: expected 'char *' but argument is
 of type 'const char *'
[ERROR]    make[1]: *** [locarchive.o] Error 1

Signed-off-by: "Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>
(transplanted from 4cd9134739b594451794cf61a6e1b137422cdafd)

scripts/build/libc/eglibc.sh

@@ -142,6 +142,7 @@ do_libc_locales() {
     # Configure with --prefix the way we want it on the target...
 
     CT_DoExecLog CFG                                                \
+    CPPFLAGS="-DNOT_IN_libc"                                        \
     "${src_dir}/configure"                                          \
         --prefix=/usr                                               \
         --cache-file="$(pwd)/config.cache"                          \