cc/gcc: add option for linker hash style

Add an option to specify the hash type that gcc will ask the linker to use.
It is a provision for the upcoming 4.7, as no version currently supports it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

# Alpha specific configuration file

## select ARCH_SUPPORTS_32

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORT_CPU

## select ARCH_SUPPORT_TUNE

##

## help The Alpha architecture.