you've to add object file or library with these functions
bu adding -l(libraryname), or objectfilename.o to your gcc command line
gcc -g test.c -lsomelib
gcc -g test.c someobject.o
you can get someobject.o by compiling package that you get, or you can get library by installing this package (i don't know it so i'm not sure how to do it .) )
if it's instalend you propably can type "man packagename" and then find name of library to link
did i help?