Use standard functions instead of calcpy() and calncpy().

* server/server.c: Use standard functions strdup() and strndup()
  instead of calcpy() and calncpy().
* server/scmapi.c: Likewise.
* proxies/ssh-proxy/lazy-ssh.c: Likewise.
* common/parsers.c, common/common.h: Likewise.
* Makefile.am, Makefile.in: Update.
* common/common.c: Remove.