Ticket #3041: fix build failure on Cygwin: redefinition of 'statvfs_works'.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
src/filemanager/mountlist.c: correct preprocessor conditions.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '3041_fix_cygwin_build'

* 3041_fix_cygwin_build:
  src/filemanager/mountlist.c: correct preprocessor conditions.
  Ticket #3041: fix build failure on Cygwin: redefinition of 'statvfs_works'.