libuv: backport android patch from 0.11.20

This patch [1] fixes compilation of the libuv test suite
when using the arm-linux-androideabi GCC toolchain
that ships with the Android NDK. The testsuite can't
actually be run anyway, because we're cross-compiling,
but the error confuses people and I want it gone.

The failure is caused by the S_IREAD and S_IWRITE flags,
which are deprecated in glibc [2], and not included in the
Android NDK's libc (bionic).

See: http://www.gnu.org/savannah-checkouts/gnu/libc/manual/html_node/Permission-Bits.html
See: https://github.com/joyent/libuv/commit/1ad61807ffa893f610f1cc87007e332582617dbf