patch [#34103] 	fileops_file_is_writable.patch, fileops_file_is_writable_2.patch
from Lawrence D'Oliveiro (ldo)

More efficient implementation of BLI_file_is_writable using access(2) instead of actually opening file.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55038 954f8c5b-7b00-dc11-b283-0030488c597c