Our latest nightly build is failing when (cross)-compiling `tor` for macOS: ``` CC src/lib/process/env.o src/lib/process/env.c:40:11: warning: implicit declaration of function '_NSGetEnviron' is invalid in C99 [-Wimplicit-function-declaration] return *_NSGetEnviron(); ^ src/lib/process/env.c:40:10: error: indirection requires pointer operand ('int' invalid) return *_NSGetEnviron(); ^~~~~~~~~~~~~~~~ 1 warning and 1 error generated. Makefile:7498: recipe for target 'src/lib/process/env.o' failed ```