libc/glibc: normalize glibc hidden version names

Hidden version names for glibc conflicted:

LIBC_GLIBC_V_2.10.1
LIBC_V_2.10

name them constantly as:
LIBC_GLIBC_V_<version>

Reported-by: Esben Haabendal <eha@doredevelopment.dk>
Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>

 # Alpha specific configuration file

 config ARCH_alpha

     select ARCH_SUPPORTS_32

     select ARCH_DEFAULT_32

     select ARCH_USE_MMU

     select ARCH_SUPPORT_CPU

     select ARCH_SUPPORT_TUNE

     help

       The Alpha architecture.