Add configure option --enable-gnu-regex to implicitly build the included GNU regex library (in case the host system doesn't provide a usable regex library).
Rename tagmanger/include/regex.h in tagmanager/include/gnuregex.h to avoid unintended inclusion in source files (this fixes the OpenSolaris crashes).
Don't use GNU regex specific regex_t::buffer element to build also without this extension (e.g. on OpenSolaris).


git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@2532 ea778897-0a13-0410-b9d1-a72fbfd435f5