ref: c28f07b5840216c4e83e1d3b21d8a9ed7c41f8f9 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); }