New or changed in 3.70:

some code improvements as suggested by Coverity. See current Coverity status here: https://scan.coverity.com/projects/498
removed the -DBUGGYGPP compile flag since now g++ can compile the code without it. The former work-arounds are still there but will be removed later.
enabled more warnings when compiling with g++ and fixed some resulting warnings.
changed the autoconf part to better support the inclusion of libzip for the pptx driver.
included a lot of documentation corrections contributed by Peter Dyballa. Many thanks!
using non case sensitive comparison when determining the target format from the file suffix.
using more STL classes instead of older private replacements (string and vector). In this context also some hard coded limits were removed.
fixed an assertion violation when using -ssp and a closepath occurred.
added the dump of the font name for the DXF format.
prototype of a "simulate fill" option for emulating filling by stroking. This is based on fillpoly.c from the hp2xx project. Thanks also to Gary Langthorne for pointing out this option. This is still kind of experimental.

(adam)