Allowing the system bashrc not to be parsed, if an env variable exists.

I think bash used not to include the system bashrc on "--rcfile myrc", but
as now it doesn't allow it anymore, let's go on the env variable.


svn path=/nixos/trunk/; revision=15779

etc/bashrc.sh

@@ -1,3 +1,6 @@
+if [ -n "$NOSYSBASHRC" ]; then
+  return
+fi
 # Initialise a bunch of environment variables.
 export PATH=/var/run/current-system/sw/bin:/var/run/current-system/sw/sbin
 export LD_LIBRARY_PATH=/var/run/opengl-driver/lib