configure improvements and fixes
MAINTAINERS update

# gpg: Signature made Wed 26 Jun 2019 21:02:10 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/trivial-patches-pull-request:
  MAINTAINERS: Change maintership of Xen code under hw/9pfs
  configure: use valid args testing sem_timedwait
  configure: disallow spaces and colons in source path and build path
  configure: set source_path only once and make its definition more robust

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>