a top-level subdirectory and it is already listed in src/Makefile.am.
The commit message introducing the change talked about libip being a "POD
library". I do not know what that is, but, hopefully, we do not really need to
make this kind of exceptions for any src/ libraries.
AUTOMAKE_OPTIONS = dist-bzip2 subdir-objects 1.5 foreign
DIST_SUBDIRS = compat lib snmplib scripts src icons errors contrib doc helpers test-suite tools
-SUBDIRS = compat lib @makesnmplib@ scripts src/ip src icons errors doc helpers test-suite tools
+SUBDIRS = compat lib @makesnmplib@ scripts src icons errors doc helpers test-suite tools
DISTCLEANFILES = include/stamp-h include/stamp-h[0-9]*
DEFAULT_PINGER = $(libexecdir)/`echo pinger | sed '$(transform);s/$$/$(EXEEXT)/'`