configure: Make sure we get a recent `nix-store'.

Dependencies

• [2] 2KJFOYGS hydra: Actually check for Nix in `configure'.
• [*] FV2M6MOT hydra: use autoconf/-make

Change contents

• edit in configure.ac at line 40
  [4.16382]

  [2.17]
  +

  + PATH="$nix:$PATH"

  + export PATH

  +

  + NEED_PROG([NIX_STORE], [nix-store])

  +

  + AC_MSG_CHECKING([whether $NIX_STORE is recent enough])

  + if "$NIX_STORE" --timeout 123 -q > /dev/null 2>&1

  + then

  + AC_MSG_RESULT([yes])

  + else

  + AC_MSG_RESULT([no])

  + AC_MSG_ERROR([`$NIX_STORE' doesn't support `--timeout'; please use a newer version.])

  + fi