cc/gcc: remove 'sub-level' version form symbols

Now we use defconfig files to store the samples, we have to be a bit more
conservatives in the symbols names, so as to avoid gigantic version bumps
when updating sub-level versions from a package.

For example (using fictitious versions):
- in crosstool-NG 1.17.0, we choose:
- latest gcc is gcc-linaro-4.7-2012.10, which is the default for the
choice in the menuconfig
- gcc-linaro-4.6-2012.10 is selected
- so, sample has an explicit symbol for the selected gcc version, as it
is not the default
- we update to crosstool-NG 1.18.0:
- latest gcc version is gcc-linaro-4.7-2013.01
- gcc-linaro-46 has been updated to gcc-linaro-4.6-2013.01
- as the sample now has no *valid* symbol to set the gcc version, the
default is used, while we would have expected to still use the 4.6
release from linaro, not the 4.7

Get rid of sub-level (ie. the third digit sequence in versions) from the
symbols for linaro versions.

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_CPU="ev56"

CT_ARCH_TUNE="ev56"

CT_ARCH_ALPHA_EV67=y

CT_KERNEL_linux=y

CT_KERNEL_V_2_6_38_8=y

CT_BINUTILS_V_2_21_1a=y

CT_CC_V_4_3_5=y

CT_CC_LANG_FORTRAN=y

CT_CC_LANG_CXX=y

# CT_CC_GCC_ENABLE_TARGET_OPTSPACE is not set

CT_LIBC_glibc=y

CT_LIBC_GLIBC_V_2_13=y

CT_LIBC_EXTRA_CC_ARGS="-Wl,--no-relax"

CT_LIBC_GLIBC_USE_PORTS=y

CT_GMP_V_5_0_1=y

CT_MPFR_V_3_0_0=y