Fix screwed logic in LIST_FOR_EACH and LIST_FOR_EACH_SAFE. They were 1. using inverse...

Fix screwed logic in LIST_FOR_EACH and LIST_FOR_EACH_SAFE. They were 1. using inverse logic and entering the loop when elem was NULL, 2. checking elem, whick is the result of CONTAINING_RECORD on the Flink pointer that should be checked for NULL. Anyway these macros are ugly and shouldn't be used, they only obfuscate the code.

svn path=/trunk/; revision=42672