pcre tests

[David Romano]

Hi everyone,

When building parrot on my iBook, two tests that depend on PCRE failed
because I don't have PCRE installed and the code that determines if
PCRE is installed is faulty. Parrot::Test::run_command returns [SIGNAL
$exit_code] if the exit code of the commands are not divisible by 256,
or if one of commands that needs to be run is not found. Attached is a
patch for both t/library/pcre.t and t/examples/library.t, the only
places where Parrot::Test::run_command is used in the test suite. With
the patch, the tests are correctly skipped.

- David

--
"Where is human nature so weak as in the bookstore?"
-- Henry Ward Beecher