Commit ba780231 ("unix,win: handle zero-sized allocations uniformly")
makes `uv__malloc()` return NULL when `size == 0`.
That's exactly the size that is passed to it when uv_spawn() tries to
spawn a process with an empty environment so handle that edge case.
Fixes: https://github.com/nodejs/node/issues/29008
PR-URL: https://github.com/libuv/libuv/pull/2408
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jameson Nash <vtjnash+github@gmail.com>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
1fc72276f9