libc/glibc: fix {e,}glibc add-ons with short or long names

Fixes the issue with {e,}glibc addons having short and long names (such as
eglibc-ports-2_13 and ports), which caused configure scripts to run
through them twice and thus configuring incorrectly.

For instance, the mips64el-n32-linux-gnu toolchain would be recognized
correctly first, but then the second pass would change it to mips32,
building a mixed MIPS-III N32 and MIPS-I libc.

Signed-off-by: Nicolás Reynolds <fauno@kiwwwi.com.ar>
[yann.morin.1992@anciens.enib.fr: remove spurious trailing spaces]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from af25723a794f2017f45c300369a6d36849e22236)

 # SPARC specific config options

 config ARCH_sparc

     select ARCH_SUPPORTS_32

     select ARCH_SUPPORTS_64

     select ARCH_DEFAULT_32

     select ARCH_USE_MMU

     select ARCH_SUPPORT_CPU

     select ARCH_SUPPORT_TUNE

     help

       The SUN SPARC architecture, as defined by:

         32 bit: http://www.sparc.org/standards/V8.pdf

         64 bit: http://www.sparc.org/standards/SPARCV9.pdf