Functions in ftcolor.c not defined

 Hi developers,
I am heading for an issue when compiling. Linker shows me this status:
undefined reference to 'FT_Palette_Set_Foreground_Color' (and so for other
functions). The function is known to my project from the header file
included but the function body is missing. I can see ftcolor.o in /obj
folder. I have not much experience with makefile.
Is there some special configuration needed ? Is there something I've missed?

Thank you,
Lenka Polaskova