arch: allow adding a suffix to the arch-part of a tuple

For some architectures, it is legit to have an alternate value in the
'architecture' part of the tuple. For example:
armv5te-*
armv7a8-*

Besides, some packages expect the tuple to reflect the arch variant
(eg. openMPI) to detect the variant's capabilities (eg. atomic
primitives).

This patch adds an option for the user to specify a suffix to be added
to the arch-part of the tuple.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Message-ID: <20130120225822.GS6838@1wt.eu>
Patch-Id: 213994
[yann.morin.1998@free.fr: make it a suffix, not an override]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

CT_EXPERIMENTAL=y

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_LOG_EXTRA=y

CT_ARCH_ARCH="armv6"

CT_ARCH_FPU="vfp"

CT_ARCH_arm=y

CT_TARGET_VENDOR="hardrpi"

CT_KERNEL_linux=y

CT_KERNEL_V_3_2_36=y

CT_BINUTILS_V_2_22=y

CT_BINUTILS_LINKER_LD_GOLD=y

CT_BINUTILS_GOLD_THREADS=y

CT_BINUTILS_LD_WRAPPER=y

CT_BINUTILS_PLUGINS=y

CT_CC_GCC_SHOW_LINARO=y

CT_CC_LANG_CXX=y

# CT_CC_STATIC_LIBSTDCXX is not set

CT_CC_GCC_DISABLE_PCH=y

CT_CC_GCC_BUILD_ID=y

CT_LIBC_EGLIBC_V_2_16=y

CT_EGLIBC_OPT_SIZE=y

CT_LIBC_GLIBC_KERNEL_VERSION_CHOSEN=y

CT_LIBC_GLIBC_MIN_KERNEL_VERSION="3.2.27"