gettext: fix build failure with locale and uclibc

As reported by Johan Sagaert in the mailing list, if it's building with
a uClibc toolchain with locale enabled the build fails since the new
gettext does a locale hack for glibc which isn't needed nor supported.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>