Make the source tree sparse clean.

With this commit, the tree compiles clean with sparse commit 87f4a7fda3d
"Teach 'already_tokenized()' to use the stream name hash table" with patch
"evaluate: Allow sizeof(_Bool) to succeed" available at
http://permalink.gmane.org/gmane.comp.parsers.sparse/2461 applied, as long
as the "include/sparse" directory is included for use by sparse (only),
e.g.:
     make CC="CHECK='sparse -I../include/sparse' cgcc"