ref: 0ca6063c8ecb32da1a63b6ca3048c0c7b93977b2 dir: /sys/src/ape/lib/ap/plan9/execl.c/
#include <unistd.h> extern char **environ; int execl(const char *name, const char *arg0, ...) { return execve(name, &arg0, environ); }