#14 exit() not defined in ptree-core.cpp

[Karl Trygve Kalleberg]

ptree-core.cpp: In function `void MopErrorMessage (char *, char *)':
ptree-core.cpp:34: `exit' undeclared (first use this function)
ptree-core.cpp:34: (Each undeclared identifier is reported only once

as reported by Vasilij Karpow.

Problem only seen on RedHat 7.0 so far. Should include testing on RH7.0 in regression tests.