This is needed when compiling with GCC >= 4.7.0 since it doesn't implicitly include 'unistd.h' anymore (needed e.g. for file operations in this particular case)
- Thanks to Luka Perkov
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@31259 3c298f89-4303-0410-b956-a3cf2f4a3e73