libselinux: bump to version 2.5

In addition, if a user is using glibc 2.22, the default CFLAG
D_FILE_OFFSET_BITS=64 will cause a compile error.  This flag is now
removed from the CFLAGS in the make file to ensure that toolchains
compiled against glibc 2.22 will build the new version of the package
properly.

In addition, libselinux now uses fts(), which is not available on musl,
and not provided by our default uClibc configuration. Therefore,
libselinux now depends on glibc, as well as all its reverse
dependencies.

Signed-off-by: Adam Duskett <Aduskett@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
[Thomas: add glibc dependency for fts().]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>