runqueue: Add support for <task>- syntax

[Richard Purdie <richard.purdie@linuxfoundation.org>]

It can be useful to run all tasks up to but not including a specific task. The
main reason this was never added was the lack of a good syntax. This patch
uses the syntax <taskname>- to denote this behaviour which is simple, not 
invasive and fits what we need from good syntax IMO, hence we can add this.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index 878028a..ee06f0e 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -634,23 +634,33 @@ class RunQueueData:
 
             fnid = taskData.build_targets[targetid][0]
             fn = taskData.fn_index[fnid]
-            self.target_pairs.append((fn, target[1]))
+            task = target[1]
+            parents = False
+            if task.endswith('-'):
+                parents = True
+                task = task[:-1]
+
+            self.target_pairs.append((fn, task))
 
             if fnid in taskData.failed_fnids:
                 continue
 
-            if target[1] not in taskData.tasks_lookup[fnid]:
+            if task not in taskData.tasks_lookup[fnid]:
                 import difflib
-                close_matches = difflib.get_close_matches(target[1], taskData.tasks_lookup[fnid], cutoff=0.7)
+                close_matches = difflib.get_close_matches(task, taskData.tasks_lookup[fnid], cutoff=0.7)
                 if close_matches:
                     extra = ". Close matches:\n  %s" % "\n  ".join(close_matches)
                 else:
                     extra = ""
-                bb.msg.fatal("RunQueue", "Task %s does not exist for target %s%s" % (target[1], target[0], extra))
-
-            listid = taskData.tasks_lookup[fnid][target[1]]
-
-            mark_active(listid, 1)
+                bb.msg.fatal("RunQueue", "Task %s does not exist for target %s%s" % (task, target[0], extra))
+  
+            # For tasks called "XXXX-", ony run their dependencies
+            listid = taskData.tasks_lookup[fnid][task]
+            if parents:
+                for i in self.runq_depends[listid]:
+                    mark_active(i, 1)
+            else:
+                mark_active(listid, 1)
 
         # Step C - Prune all inactive tasks
         #