The problem was solved by understanding Eclipse illogic quircks and funny moves. It was caused by crossed out .c files which happened to be by default, crazy but true. I solved it by menu Project => Properties => C/C++ Build General => Paths and Symbols -> Source Location: Selecting path and Edit Filter. Beware Eclipse’s visibility to dependencies (inclusions and the likes) is set by multiple different Eclipse settings. Where one setting includes libraries (folders and/or files) another setting filters out sections of libraries (folders and files). And the beginning user not familiar with Eclipse’s oddities is left confused.