Details
Major Description
On OSX, pkg-config --exists activemq-cpp returns the wrong value.
That is because the activemq-cpp.pc file contains the line Requires.private: apr-1-config.
APR's .pc file however is called apr-1 (minus the -config), which is why pkg-config thinks there's an unresolved dependency.
AFAICS, the reason for this is that the sed script in m4/apr_tools.m4:83 does the wrong thing with Apples BSD sed, leaving the -config in, when it should throw it away.