[libcxx] Use Fuchsia-native monotonic clock for std::chrono::steady_clock
Use the zx_clock_get_monotonic system call directly rather than
going through the POSIX clock_gettime function. The libc function
is a trivial wrapper around the system call, and is not a standard C
function. Avoiding it reduces the Fuchsia libc ABI surface that
libc++ depends on.
Reviewed By: phosek, ldionne, #libc
Differential Revision: https://reviews.llvm.org/D116606
NOKEYCHECK=True
GitOrigin-RevId: ce167c6fb2ae67cffa6702b869762fb80b62d3bc
1 file changed