configure: pass the allowed lib extensions to check_for()

Rather than building all possible library names in the caller,
lets just do it once in check_for.

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

# m68k specific configuration file

## depends on EXPERIMENTAL

##

## select ARCH_SUPPORTS_32

## select ARCH_DEFAULT_32

## select ARCH_DEFAULT_BE

## select ARCH_SUPPORT_CPU

##

## help The m68k architecture