[gnome-build-meta] project.conf: Provide access to pulseaudio from within `bst shell`

[Tristan Van Berkom <tvb src gnome org>]

commit e51367ef5e3ec5b7cd9d253de8bf4fb45629b7d4
Author: Tristan Van Berkom <tristan vanberkom codethink co uk>
Date:   Tue Mar 6 20:17:55 2018 +0900

    project.conf: Provide access to pulseaudio from within `bst shell`
    
    This leverages some new features to expose the host XDG_RUNTIME_DIR
    into the runtime where the pulseaudio socket will reside, and to
    set the PULSE_SERVER environment so that applications using
    pulseaudio will be able to talk to the host side audio server.
    
    Also, with format version 4 we remove `environment-inherit` as it
    is redundant with the newly added `environment` configuration.

 project.conf | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)
---
diff --git a/project.conf b/project.conf
index db1037d..9a4056e 100644
--- a/project.conf
+++ b/project.conf
@@ -2,7 +2,7 @@
 name: gnome
 
 # The minimum base BuildStream format
-format-version: 3
+format-version: 4
 
 # Where elements are stored
 element-path: elements
@@ -117,10 +117,18 @@ shell:
   command: [ 'bash', '--noprofile', '--norc', '-i' ]
 
   # Some environment variables to inherit from the host environment
-  environment-inherit:
-  - LANG
-  - DISPLAY
-  - DBUS_SESSION_BUS_ADDRESS
+  environment:
+    LANG: '$LANG'
+    DISPLAY: '$DISPLAY'
+    DBUS_SESSION_BUS_ADDRESS: '$DBUS_SESSION_BUS_ADDRESS'
+    XDG_RUNTIME_DIR: '$XDG_RUNTIME_DIR'
+
+    # We dont automatically mount the user's home, but this makes things work
+    # better if the user decides to mount in their homedir explicitly with `bst shell`
+    HOME: '$HOME'
+
+    # Inform applications which use pulseaudio of the server socket
+    PULSE_SERVER: 'unix:${XDG_RUNTIME_DIR}/pulse/native'
 
   # Some things to mount into the sandbox
   host-files:
@@ -149,3 +157,8 @@ shell:
 
   # Allow access to sysfs, needed for local device discovery
   - '/sys'
+
+  # Allow access to the user runtime directory, this
+  # will include the pulseaudio socket along with some
+  # other things.
+  - '${XDG_RUNTIME_DIR}'