_Roxen: Fixed buffer overrun in http_decode_string().

Also increases the strictness of a few related testsuite tests.
SSL: Added some notes about destroy().
Tools.Standalone.git_export_autodoc: Speed up repeated runs.

Persisting of the export state for commits lacking documentation was
lost in the non-doc detection commit. This caused some commits lacking
documentation to be reprocessed every run of the extractor, and slowed
down such runs from completing in a few seconds to taking ~ an hour.
Build: SOL_TCP is called IPPROTO_TCP in Solaris.

Fixes compilation issues on Solaris 11.
Build: Fixed some typos in pervious commit.
Stdio.Buffer: Use the correct macro...
Tools.Standalone.git_export_autodoc: Improved robustness.
String.Buffer: completed the removal of addat
Tools.Standalone.autodoc_to_html: Improved robustness.

Fixed NULL-deref in output_from_type().
sprintf: fix last argument handling with _sprintf lfuns

Since I broke this in 7fdf942f6b5344b7d52c141441913f283661006a, sprintf
did not properly keep track of the last argument when calling _sprintf
lfuns.