Replace the libc environment with a thread-safe emulation

putenv(3) and friends aren't thread-safe regardless of how you slice
it; a global lock around all environment operations (like before)
keeps things safe as far as our own operations go, but we have
absolutely no control over what libc or a library dragged in by a
driver/NIF does -- they're free to call getenv(3) or putenv(3)
without honoring our lock.

This commit solves this by setting up an "emulated" environment which
can't be touched without going through our interfaces. Third-party
libraries can still shoot themselves in the foot but benign uses of
os:putenv/2 will no longer risk crashing the emulator.

1 files changed, 0 insertions, 0 deletions

diff --git a/bootstrap/lib/kernel/ebin/os.beam b/bootstrap/lib/kernel/ebin/os.beam
index 98c44e8fba..61ed6a107a 100644
--- a/bootstrap/lib/kernel/ebin/os.beam
+++ b/bootstrap/lib/kernel/ebin/os.beam