bitbake/utils.py: Ensure utils.which() returns full paths

If the path passed to which contains empty elements, it will search
the current working directory for the file which is correct baheviour.

Various pieces of code assume the path returned is a full path though.
This commit ensures we don't return relative paths.

(Bitbake rev: 4de24ccc10e40cc088b8515095df59f69b12715d)

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

bitbake/lib/bb/utils.py

@@ -721,6 +721,8 @@ def which(path, item, direction = 0):
     for p in paths:
         next = os.path.join(p, item)
         if os.path.exists(next):
+            if not os.path.isabs(next):
+                next = os.path.abspath(next)
             return next
 
     return ""