Fix clang 3.5.0 warning in libarchive (via usr.bin/cpio)

[dim]

Summary

Fix the following -Werror warning from clang 3.5.0, while building usr.bin/cpio on amd64 (or any arch with 64-bit time_t):

usr.bin/cpio/../../contrib/libarchive/cpio/cpio.c:1143:6: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value]
        if (abs(mtime - now) > (365/2)*86400)
            ^
usr.bin/cpio/../../contrib/libarchive/cpio/cpio.c:1143:6: note: use function 'labs' instead
        if (abs(mtime - now) > (365/2)*86400)
            ^~~
            labs
1 error generated.

This is because time_t is a long on amd64. To avoid the warning, just copy the equivalent test from a few lines before, which is used in the Windows case, and which is type safe.

[emaste]

Looks good to me. Should send upstream too https://github.com/libarchive/libarchive

[dim]

Ah, on IRC somebody mentioned that FreeBSD base is basically the "upstream" for libarchive now? :)

[dim]

Sent upstream as: https://github.com/libarchive/libarchive/pull/94

[dim]

Closed by commit rS274846 (authored by @dim).