Looks OK. Some comments below.
http://codereview.appspot.com/4431071/diff/1/gcc/c-family/c.opt
File gcc/c-family/c.opt (right):
http://codereview.appspot.com/4431071/diff/1/gcc/c-family/c.opt#newcode943
gcc/c-family/c.opt:943:
+fpph-dump-tree
+C++ Var(flag_pph_dump_tree)
+-fpph-dump-tree
Add a flag -fpph-dump-tree to dump the namespace trees read and written by PPH.
This dump could use some clarification, but it can wait for another day.
Replace PPH calls to pushdecl_with_scope with pushdecl_into_namespace. It
turns out that pushdecl_with_scope always inserts into the current n
