This being the first 3rdparty-contribution, we may want to consider the
structure of the project file generation scripts. Perhaps add small,
constribution-specific scripts to each directory in 3rdparty instead of adding
all constraints to generate_visualc_files.pl?
Inherit PlatformToolset from the project configuration. This allow the
project to configure PlatformToolset, and aligns the Release x64 build
with other build types.
Fixes#1430
