bitbake: show more information for NoProvider errors

"Nothing PROVIDES" errors often come up when a recipe has been skipped
for some reason, and therefore it is useful to print out that reason
information when showing the error so that the user understands why the
error has occurred.

Given that we already feed the reason information into the skiplist for
various situations (COMMERCIAL_LICENSE, COMPATIBLE_MACHINE etc.) this
should now output a useful error message for skipped recipes.

Fixes [YOCTO #846], [YOCTO #1127]

(Bitbake rev: 6765218430e31c165888f26fbc75023c89a6eab2)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cache.py

@@ -43,7 +43,7 @@ except ImportError:
     logger.info("Importing cPickle failed. "
                 "Falling back to a very slow implementation.")
 
-__cache_version__ = "141"
+__cache_version__ = "142"
 
 def getCacheFile(path, filename):
     return os.path.join(path, filename)
@@ -99,6 +99,7 @@ class CoreRecipeInfo(RecipeInfoCommon):
 
         self.skipreason = self.getvar('__SKIPPED', metadata)
         if self.skipreason:
+            self.pn = self.getvar('PN', metadata) or bb.parse.BBHandler.vars_from_file(filename,metadata)[0]
             self.skipped = True
             self.provides  = self.depvar('PROVIDES', metadata)
             self.rprovides = self.depvar('RPROVIDES', metadata)