add weak `memcpy` et al symbols#29

Merged

japaric merged 7 commits intomasterfrom

Aug 16, 2016

Commits on Aug 15, 2016

add weak `memcpy` et al symbols
Jorge Aparicio
committed
exclude windows and macos
Jorge Aparicio
committed
check presence of weak symbols
Jorge Aparicio
committed
use rlibc crate instead
Jorge Aparicio
committed
remove unused feature gates
Jorge Aparicio
committed

Commits on Aug 16, 2016

adjust test: weak symbols are now in librlibc.rlib
Jorge Aparicio
committed
add core_intrinsics feature gate
Jorge Aparicio
committed