erlang运行期可通过环境变量定制的参数

从R12B-0源码里面摘录出来的，挺有用的，我就不标注了，从名字好容易看出用途。

erts\emulator\beam\break.c(478):    char* mode = getenv("ERL_CONSOLE_MODE");
erts\emulator\beam\break.c(681):    dumpname = getenv("ERL_CRASH_DUMP");
erts\emulator\beam\erl_init.c(628):    tmpenvbuf = getenv("ERL_FULLSWEEP_AFTER");
erts\emulator\beam\erl_init.c(634):    tmpenvbuf = getenv("ERL_THREAD_POOL_SIZE");
erts\emulator\beam\io.c(1248):    maxports = getenv("ERL_MAX_PORTS");
erts\emulator\drivers\common\efile_drv.c(556):    char *p = getenv("ERL_EFILE_THREAD_SHORT_CIRCUIT");
erts\emulator\drivers\unix\ttsl_drv.c(564):    if (!(c = getenv("TERM")) || tgetent((char*)lbuf, c) <= 0)
erts\emulator\drivers\win32\win_con.c(1671):    char* title = getenv("ERL_WINDOW_TITLE");
erts\emulator\sys\unix\sys.c(482):    bindir = getenv("BINDIR");
erts\emulator\sys\unix\sys.c(630):    env = getenv("ERL_CRASH_DUMP_NICE");
erts\emulator\sys\unix\sys.c(640):    env = getenv("ERL_CRASH_DUMP_SECONDS");
erts\emulator\sys\unix\sys.c(2838): char *no_kp = getenv("ERL_NO_KERNEL_POLL");
erts\emulator\sys\vxworks\sys.c(684):  if ((stackenv = getenv("ERLPORTSTACKSIZE")) != NULL &&
erts\emulator\sys\win32\sys.c(233):    char* mode = getenv("ERL_CONSOLE_MODE");
erts\etc\common\dialyzer.c(109):    emulator = getenv("DIALYZER_EMULATOR");
erts\etc\common\erlc.c(122):    emulator = getenv("ERLC_EMULATOR");
erts\etc\common\erlexec.c(310):    s = getenv("ERL_CONSOLE_MODE");
erts\etc\common\erlexec.c(312): s = getenv("ERL_EMULATOR_DLL");
erts\etc\common\erlexec.c(356):    malloc_lib = getenv("ERL_MALLOC_LIB");
erts\etc\common\erlexec.c(464):    if ((s = getenv("PATH")) == NULL) {
erts\etc\common\erlexec.c(1101):    reldir = getenv("RELDIR");
erts\etc\common\erlexec.c(1246):    homedrive = getenv("HOMEDRIVE");
erts\etc\common\erlexec.c(1247):    homepath = getenv("HOMEPATH");
erts\etc\common\erlexec.c(1266):    progname = getenv("PROGNAME");
erts\etc\common\erlexec.c(1267):    bindir = getenv("BINDIR");
erts\etc\common\erlexec.c(1268):    rootdir = getenv("ROOTDIR");
erts\etc\common\erlexec.c(1269):    emu = getenv("EMU");
erts\etc\common\erlexec.c(1278):    home = getenv("HOME");
erts\etc\common\escript.c(109):    emulator = getenv("ESCRIPT_EMULATOR");
erts\etc\common\heart.c(666):    comspec = getenv("COMSPEC");
erts\etc\common\inet_gethost.c(319):    if ((dls = getenv("ERL_INET_GETHOST_DEBUG")) != NULL) {
erts\etc\unix\run_erl.c(235):  if ((p = getenv("RUN_ERL_LOG_ALIVE_MINUTES"))) {
erts\etc\unix\run_erl.c(246):  if ((p = getenv("RUN_ERL_LOG_ACTIVITY_MINUTES"))) {
erts\etc\unix\run_erl.c(253):  if ((p = getenv("RUN_ERL_LOG_ALIVE_FORMAT"))) {
erts\etc\unix\run_erl.c(262):  if ((p = getenv("RUN_ERL_LOG_ALIVE_IN_UTC")) && strcmp(p,"0")) {
erts\etc\unix\run_erl.c(265):  if ((p = getenv("RUN_ERL_LOG_GENERATIONS"))) {
erts\etc\unix\run_erl.c(273):  if ((p = getenv("RUN_ERL_LOG_MAXSIZE"))) {
erts\etc\vxworks\erl.exec.c(71):    if ((rootdir = getenv("ROOTDIR")) == NULL ||
erts\etc\vxworks\erl.exec.c(72): (bindir = getenv("BINDIR")) == NULL ||
erts\etc\vxworks\erl.exec.c(73): (progname = getenv("PROGNAME")) == NULL) {
erts\etc\vxworks\erl.exec.c(79):    if ((home = getenv("HOME")) == NULL)
erts\etc\vxworks\erl_io.c(61):    if ((stackenv = getenv("ERLSTACKSIZE")) == NULL)
erts\etc\win32\win_erlexec.c(212): if ((title = getenv("ERL_WINDOW_TITLE")) != NULL) {
lib\asn1\c_src\asn1_erl_driver.c(157):  if ((ptr = getenv("ASN1_MIN_BUF_SIZE")) == NULL)
lib\erl_interface\src\connect\ei_connect.c(447):    if ((dbglevel = getenv("EI_TRACELEVEL")) != NULL ||
lib\erl_interface\src\connect\ei_connect.c(448): (dbglevel = getenv("ERL_DEBUG_DIST")) != NULL)
lib\erl_interface\src\connect\ei_connect.c(1663):    homedrive = getenv("HOMEDRIVE");
lib\erl_interface\src\connect\ei_connect.c(1664):    homepath = getenv("HOMEPATH");
lib\erl_interface\src\connect\ei_connect.c(1667):    homepath = getenv("HOME");