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>

# Compute AVR32-specific values

CT_DoArchTupleValues() {

    # The architecture part of the tuple:

    CT_TARGET_ARCH="${CT_ARCH}"

    # gcc ./configure flags

    CT_ARCH_WITH_ARCH=

    CT_ARCH_WITH_ABI=

    CT_ARCH_WITH_CPU=

    CT_ARCH_WITH_TUNE=

    CT_ARCH_WITH_FPU=

    CT_ARCH_WITH_FLOAT=

    CT_TARGET_SYS=none

}