libstore: Always mount `/dev/pts' individually.

This fixes problems such as Tcl's PTY handling:

  ERROR: The system has no more ptys.  Ask your system administrator to
  create more.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 538990ed9..2a8ddd491 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1750,6 +1750,11 @@ void DerivationGoal::startBuilder()
            host file system. */
         Paths defaultDirs;
         defaultDirs.push_back("/dev");
+
+	/* The `/dev/pts' directory must be mounted separately so that
+	   newly-created pseudo-terminals show up.  */
+        defaultDirs.push_back("/dev/pts");
+
         defaultDirs.push_back("/proc");
         Paths dirsInChroot = querySetting("build-chroot-dirs", defaultDirs);