Update major version.

Now libwrap depends on libc.so.4, so needs to update the major version.
  Without this, old binaries which use libwrap and build with libc.so.3
  will coredump on recent 4.0.

Approved by: jkh

Reviewed by: markm

lib/libwrap/Makefile

@@ -5,6 +5,8 @@
 MAINTAINER=markm@FreeBSD.org
 
 LIB=	wrap
+SHLIB_MAJOR= 3
+SHLIB_MINOR= 0
 MAN3=   hosts_access.3
 MAN5=	hosts_access.5 hosts_options.5