Update to 2.4.2

"I have changed postgis dependency to postgis22 since it used by
default by QGis and other GIS. (Still annoying since we don't have a
post-office framework:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213038)

Changes for 2.4.2:
Improvement

Works for postgreSQL 10

Bug fixes

Fixed: Unexpected error column "cname"
Replace linux with GLIBC for glibc-specific headers and functions

To see the list of closed issues:
https://github.com/pgRouting/pgrouting/milestone/21?closed=1
"

PR: 221576
Submitted by: lbartoletti@tuxfamily.org (maintainer)