libfl.a は何だっけ?っとおもって中身をみようと思った。
takuya@air:~/repos/gnu_make/chap02/2.8$ ar rv libcounter.a counter.o lexer.o r - lexer.o a - counter.o takuya@air:~/repos/gnu_make/chap02/2.8$ ar rv libcounter.a counter counter.d counter.o takuya@air:~/repos/gnu_make/chap02/2.8$ ar rv libcounter.a counter.o r - counter.o takuya@air:~/repos/gnu_make/chap02/2.8$ ar rv libcounter.a lexer.o r - lexer.o takuya@air:~/repos/gnu_make/chap02/2.8$ cc count_words.o libcounter.a /usr/lib/libfl.a -o count_words または cc count_words.o libcounter.a -lfl -o count_words