configure should check for libboost-regex

[spth]

When building I got an error
/usr/bin/ld: cannot find -lboost_regex
since I had libboost-regex-dev notinstalled.
./configure should have caught that issue.

Philipp

[frx774]

In case anyone else's google searching brought them ultimately to this Issue, note that I have a fork in which I have eliminated the libboost-regex dependency. (This dependency is completely unnecessary as that library is not actually utilized--the sole API invocation from that library happens to be commented-out. Thus, eliminating this dependency is a rather straightforward matter of removing references to '-lboost_regex' in a handful of files.