Eclipse Falsely Reports 3 Functions As Undefined
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.