update lcpp
add configuration for linux
fix wrong support for #include_next
some tweak for clang's __has_include_next
allow duplicate functional macro which has same expansion
ffi.defs supports functional macro
allow C variable declaration which name is same as functional macro
allow empty macro argument
trim first and last spaces in macro argument
support macro which is resolved itself.
implement practical behavior that #include "..." search files in same directory of callee header.
add skip setting and extra path to include