build: prohibit cross-inclusion

Make it easier to detect invalid cross-directory includes, by
adding a syntax check.  The check is designed to be extensible:
the default case lists only the non-driver directories, and
specific directories can list a different set (for example,
util/ can only use itself, network/ can only use itself, util/,
or conf/).

* .gnulib: Update to latest, for syntax check improvment.
* cfg.mk (sc_prohibit_cross_inclusion): New check.
(sc_prohibit_strncmp, sc_libvirt_unmarked_diagnostics): Simplify.

1 files changed, 0 insertions, 0 deletions

diff --git a/.gnulib b/.gnulib
-Subproject b856fadc1c8dcb53e7efcbb2d0ae7edc022fdb6
+Subproject d5612c714c87555f1059d71d347e20271dced32