Replace boilerplate checks with accurate checks.
Replace boilerplate checks with accurate checks.

Remove all the unused checks for headers and library functions, only
check for what is actually needed.

Divide checks so that it can be more clear which ones are used by feng
proper and which ones are used by the configuration parsing code.

lscube/feng,lscube/feng,lscube/feng,winlinvip/feng,winlinvip/feng,winlinvip/feng