lex tests pass and fail even though lex/flex is not installed

[Leo Davis]

versions: automake (GNU automake) 1.7.2
          autoconf (GNU Autoconf) 2.57

When I did `make check' I had the following results with the lex test scripts:

PASS: lex.test
PASS: lex2.test
FAIL: lex3.test
PASS: lex4.test
FAIL: lex5.test

So after checking into why lex3.test failed I noticed the following tests 
discovered by `configure'

checking for flex... no
checking for lex... no

It turns out that lex.yy.c and foo.c get created when make is run (by 
`missing'), so the test carries on to its inevitable failure.  I guess I was 
expecting the tests to be neither PASS nor FAIL, but SKIP (after all it did 
correctly detect that these programs aren't there).

Thanks for automake!  It's been a great tool.