Better default permissions for created directories
Better default permissions for created directories

Change the support code for directory creation so that it sets all
permission bits (ugo=rwx). The process's currently active umask will be
subtracted from these permissions, which leads to the result that (for a
standard umask of "022") directories are created with a mode of "0755".

So by default, directories created with `prim__createDir` are now also
group-executable and other-executable by default.

Previous behaviour was to create the directories readable for group and
other, but not executable (mode "744"), and thus inaccessible to anyone
except the owner.

mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm