* tools/tiffcp.c: fix read of undefined variable in case of missing
required tags. Found on test case of MSVR 35100.
* tools/tiffcrop.c: fix read of undefined buffer in
readContigStripsIntoBuffer() due to uint16 overflow. Probably not a
security issue but I can be wrong. Reported as MSVR 35100 by Axel
Souchet from the MSRC Vulnerabilities & Mitigations team.