build.sh

rm lib_kernel.so lib_kernel.o
gcc -O2 -fno-common -c -o lib_kernel.o lib_kernel.c
gcc -bundle -undefined dynamic_lookup -o lib_kernel.so lib_kernel.o 

lib_kernel.c

#define LUA_LIB
#include <lua.h>
#include <lualib.h>
#include "lauxlib.h"
#define LUA_KERNELLIBNAME "kernel"

static int lib_kernel_sleep(lua_State *L)
{
    // int m = static_cast<int> (luaL_checknumber(L,1));
    int m = luaL_checknumber(L,1);
    usleep(m * 1000); 
    // usleep takes nanoseconds. This converts the parameter to milliseconds. 
    // Change this as necessary. 
    // Alternatively, use 'sleep()' to treat the parameter as whole seconds. 
    return 0;
}

static const luaL_reg kernellib[] = {
  {"sleep",   lib_kernel_sleep},
  {NULL,		NULL}
};

LUALIB_API int luaopen_lib_kernel (lua_State *L) {
  luaL_register(L, LUA_KERNELLIBNAME, kernellib);
  return 1;
}