MINOR: Makefile deviceatlas (2 replies)

Hello,

here a tiny change, the USE_PCRE can be easily get forgotten and the user
might not necessarly understand the further linkage problem.

Not urgent though, just faced one time the problem, would be nice to find
it for 1.6.3 otherwise it is ok.

Please cc ttrnka@deviceatlas.com for any response.

Thanks in advance.
Kindest regards.