OSPL-1717 Make 'gnumake' set the custom file gen libpath using
the export keyword.
OSPL-2874 Support windows paths in makefiles (who'd a thunk it...)
Add -O3 as the default optmized compiler level. Compilers that don't
support should define 'genflags' value template variable to something
they do instead.
OSPL-2894 Leave value of gnumake undefined - this is different to
explicitly undefining it. The latter can only be overridden
with a --value_template argument.
OSPL-2894 Get the pathing of the custom types libpaths working
when gnumake is set for the *first* platform. We assume if one is set,
all are set.
OSPL-0 For reasons unclear we weren't putting NDEBUG on "Release"
Merge remote-tracking branch 'internal/OSPL_FORK'