build: use bb.process instead of os.system

(Bitbake rev: 53740977521bc81ffa37adfa7bbeb8f2a80ea165)

build: write logfiles per task, not per function
Based on d14f9bf6 from poky, reworked for master and other cleanup.

(Bitbake rev: beadff2eca1eb95f0411115dd72ddb4c3c44c604)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/data_smart.py

@@ -291,13 +291,13 @@ class DataSmart(MutableMapping):
             self._makeShadowCopy(var)
         self.dict[var][flag] = flagvalue
 
-    def getVarFlag(self, var, flag, exp = False):
+    def getVarFlag(self, var, flag, expand = False):
         local_var = self._findVar(var)
         value = None
         if local_var:
             if flag in local_var:
                 value = copy.copy(local_var[flag])
-        if exp and value:
+        if expand and value:
             value = self.expand(value, None)
         return value