glcpp: Don't strlen() the output for every token being printed.

glcpp: Don't strlen() the output for every token being printed.

The ralloc string appending functions were originally intended for
simple, non-hot-path uses like printing to an info log.

Cuts Unigine Tropics load time by around 20% (6 seconds).

v2: Avoid strlen() on every newline, too.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> [v1]
Acked-by: José Fonseca <jfonseca@vmware.com> [v1]