Test strerror_r on Android and Linux

libc-test/build.rs

src/unix/bsd/mod.rs

src/unix/haiku/mod.rs

src/unix/hermit/mod.rs

src/unix/mod.rs

src/unix/newlib/mod.rs

src/unix/notbsd/android/mod.rs

src/unix/notbsd/emscripten/mod.rs

src/unix/notbsd/linux/mod.rs

src/unix/redox/mod.rs

src/unix/solarish/mod.rs

src/unix/uclibc/mod.rs