https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31874&sort=-opened&can=1&q=proj%3Agrok

and throw in a little refactoring

Note:

1. configure.ac and libtiff-4.pc.in were moved from higher level
directory in libtiff repo into thirdparty/libtiff directory in
grok repo

2. cmake folder was copied into /thirdparty directory in grok repo