unix: Use standard return codes for main
unix: Use standard return codes for main

As in the CPython manual: "Unix programs generally use 2 for
command line syntax errors and 1 for all other kind of errors"

dhylands/micropython,TDAbboud/micropython,KISSMonX/micropython,martinribelotta/micropython,ericsnowcurrently/micropython,Timmenem/micropython,emfcamp/micropython,mianos/micropython,omtinez/micropython,suda/micropython,oopy/micropython,praemdonck/micropython,TDAbboud/micropython,Vogtinator/micropython,noahchense/micropython,martinribelotta/micropython,jlillest/micropython,paul-xxx/micropython,danicampora/micropython,tobbad/micropython,EcmaXp/micropython,jmarcelino/pycom-micropython,tuc-osg/micropython,jimkmc/micropython,aethaniel/micropython,emfcamp/micropython,ceramos/micropython,galenhz/micropython,HenrikSolver/micropython,martinribelotta/micropython,hiway/micropython,blmorris/micropython,matthewelse/micropython,vriera/micropython,methoxid/micropystat,swegener/micropython,utopiaprince/micropython,rubencabrera/micropython,praemdonck/micropython,tdautc19841202/micropython,matthewelse/micropython,ericsnowcurrently/micropython,Timmenem/micropython,stonegithubs/micropython,jmarcelino/pycom-micropython,ChuckM/micropython,neilh10/micropython,redbear/micropython,toolmacher/micropython,alex-robbins/micropython,utopiaprince/micropython,torwag/micropython,adafruit/micropython,mpalomer/micropython,tralamazza/micropython,firstval/micropython,ryannathans/micropython,xhat/micropython,mianos/micropython,aethaniel/micropython,neilh10/micropython,orionrobots/micropython,aethaniel/micropython,suda/micropython,trezor/micropython,pozetroninc/micropython,paul-xxx/micropython,lowRISC/micropython,ganshun666/micropython,TDAbboud/micropython,neilh10/micropython,KISSMonX/micropython,tdautc19841202/micropython,warner83/micropython,turbinenreiter/micropython,dinau/micropython,kerneltask/micropython,jimkmc/micropython,pozetroninc/micropython,jmarcelino/pycom-micropython,hiway/micropython,KISSMonX/micropython,turbinenreiter/micropython,vitiral/micropython,chrisdearman/micropython,omtinez/micropython,blmorris/micropython,firstval/micropython,PappaPeppar/micropython,SungEun-Steve-Kim/test-mp,ceramos/micropython,selste/micropython,deshipu/micropython,TDAbboud/micropython,paul-xxx/micropython,suda/micropython,bvernoux/micropython,noahwilliamsson/micropython,MrSurly/micropython-esp32,vitiral/micropython,turbinenreiter/micropython,henriknelson/micropython,bvernoux/micropython,methoxid/micropystat,orionrobots/micropython,jimkmc/micropython,Peetz0r/micropython-esp32,bvernoux/micropython,KISSMonX/micropython,infinnovation/micropython,henriknelson/micropython,pfalcon/micropython,blazewicz/micropython,SungEun-Steve-Kim/test-mp,chrisdearman/micropython,cnoviello/micropython,swegener/micropython,tralamazza/micropython,pramasoul/micropython,matthewelse/micropython,PappaPeppar/micropython,alex-march/micropython,adafruit/micropython,aethaniel/micropython,jmarcelino/pycom-micropython,mgyenik/micropython,MrSurly/micropython-esp32,warner83/micropython,pfalcon/micropython,xhat/micropython,micropython/micropython-esp32,xhat/micropython,drrk/micropython,firstval/micropython,noahwilliamsson/micropython,EcmaXp/micropython,cnoviello/micropython,Timmenem/micropython,emfcamp/micropython,pfalcon/micropython,drrk/micropython,lbattraw/micropython,puuu/micropython,jimkmc/micropython,cnoviello/micropython,stonegithubs/micropython,mianos/micropython,orionrobots/micropython,adamkh/micropython,MrSurly/micropython-esp32,mgyenik/micropython,misterdanb/micropython,mpalomer/micropython,praemdonck/micropython,selste/micropython,galenhz/micropython,hosaka/micropython,tralamazza/micropython,dhylands/micropython,alex-robbins/micropython,neilh10/micropython,pramasoul/micropython,adafruit/circuitpython,puuu/micropython,SungEun-Steve-Kim/test-mp,xuxiaoxin/micropython,galenhz/micropython,MrSurly/micropython,pramasoul/micropython,lbattraw/micropython,ruffy91/micropython,misterdanb/micropython,ruffy91/micropython,vitiral/micropython,danicampora/micropython,micropython/micropython-esp32,tobbad/micropython,ChuckM/micropython,kerneltask/micropython,skybird6672/micropython,mhoffma/micropython,matthewelse/micropython,lowRISC/micropython,cloudformdesign/micropython,suda/micropython,selste/micropython,supergis/micropython,cloudformdesign/micropython,torwag/micropython,tobbad/micropython,cloudformdesign/micropython,tdautc19841202/micropython,ahotam/micropython,ahotam/micropython,tobbad/micropython,praemdonck/micropython,trezor/micropython,infinnovation/micropython,henriknelson/micropython,HenrikSolver/micropython,stonegithubs/micropython,micropython/micropython-esp32,jlillest/micropython,supergis/micropython,ahotam/micropython,tuc-osg/micropython,emfcamp/micropython,utopiaprince/micropython,HenrikSolver/micropython,kerneltask/micropython,slzatz/micropython,danicampora/micropython,alex-march/micropython,oopy/micropython,stonegithubs/micropython,adafruit/micropython,feilongfl/micropython,mgyenik/micropython,ernesto-g/micropython,rubencabrera/micropython,hiway/micropython,swegener/micropython,suda/micropython,feilongfl/micropython,PappaPeppar/micropython,firstval/micropython,infinnovation/micropython,blmorris/micropython,trezor/micropython,omtinez/micropython,dinau/micropython,bvernoux/micropython,trezor/micropython,dhylands/micropython,xyb/micropython,Timmenem/micropython,SHA2017-badge/micropython-esp32,vriera/micropython,Timmenem/micropython,slzatz/micropython,MrSurly/micropython,adamkh/micropython,EcmaXp/micropython,hosaka/micropython,AriZuu/micropython,methoxid/micropystat,mhoffma/micropython,lbattraw/micropython,toolmacher/micropython,Vogtinator/micropython,warner83/micropython,jmarcelino/pycom-micropython,adafruit/circuitpython,pozetroninc/micropython,PappaPeppar/micropython,swegener/micropython,AriZuu/micropython,mpalomer/micropython,matthewelse/micropython,SungEun-Steve-Kim/test-mp,kostyll/micropython,ahotam/micropython,danicampora/micropython,torwag/micropython,Peetz0r/micropython-esp32,toolmacher/micropython,micropython/micropython-esp32,ceramos/micropython,kostyll/micropython,xyb/micropython,xuxiaoxin/micropython,toolmacher/micropython,turbinenreiter/micropython,feilongfl/micropython,ericsnowcurrently/micropython,ruffy91/micropython,heisewangluo/micropython,mhoffma/micropython,mpalomer/micropython,dinau/micropython,kostyll/micropython,pfalcon/micropython,adamkh/micropython,chrisdearman/micropython,blazewicz/micropython,ernesto-g/micropython,heisewangluo/micropython,orionrobots/micropython,stonegithubs/micropython,hosaka/micropython,cnoviello/micropython,puuu/micropython,ericsnowcurrently/micropython,orionrobots/micropython,chrisdearman/micropython,cnoviello/micropython,adafruit/circuitpython,dmazzella/micropython,dxxb/micropython,redbear/micropython,mgyenik/micropython,henriknelson/micropython,Peetz0r/micropython-esp32,skybird6672/micropython,Peetz0r/micropython-esp32,toolmacher/micropython,alex-march/micropython,MrSurly/micropython,AriZuu/micropython,adafruit/micropython,methoxid/micropystat,paul-xxx/micropython,ganshun666/micropython,slzatz/micropython,AriZuu/micropython,dmazzella/micropython,adamkh/micropython,AriZuu/micropython,ganshun666/micropython,SHA2017-badge/micropython-esp32,tuc-osg/micropython,deshipu/micropython,pfalcon/micropython,ernesto-g/micropython,galenhz/micropython,mianos/micropython,redbear/micropython,oopy/micropython,ChuckM/micropython,noahchense/micropython,mhoffma/micropython,alex-march/micropython,ganshun666/micropython,tuc-osg/micropython,torwag/micropython,ericsnowcurrently/micropython,ryannathans/micropython,skybird6672/micropython,cloudformdesign/micropython,tuc-osg/micropython,misterdanb/micropython,galenhz/micropython,danicampora/micropython,SungEun-Steve-Kim/test-mp,dxxb/micropython,Vogtinator/micropython,xyb/micropython,xyb/micropython,oopy/micropython,lowRISC/micropython,MrSurly/micropython-esp32,deshipu/micropython,blmorris/micropython,matthewelse/micropython,supergis/micropython,lbattraw/micropython,supergis/micropython,pozetroninc/micropython,redbear/micropython,ernesto-g/micropython,Peetz0r/micropython-esp32,SHA2017-badge/micropython-esp32,adafruit/circuitpython,vriera/micropython,emfcamp/micropython,ChuckM/micropython,tdautc19841202/micropython,oopy/micropython,jlillest/micropython,martinribelotta/micropython,selste/micropython,dhylands/micropython,praemdonck/micropython,aethaniel/micropython,utopiaprince/micropython,redbear/micropython,puuu/micropython,MrSurly/micropython,chrisdearman/micropython,MrSurly/micropython-esp32,dxxb/micropython,KISSMonX/micropython,alex-march/micropython,ceramos/micropython,omtinez/micropython,swegener/micropython,paul-xxx/micropython,alex-robbins/micropython,HenrikSolver/micropython,dhylands/micropython,cwyark/micropython,pramasoul/micropython,ChuckM/micropython,PappaPeppar/micropython,cwyark/micropython,feilongfl/micropython,heisewangluo/micropython,cwyark/micropython,kerneltask/micropython,ryannathans/micropython,cloudformdesign/micropython,turbinenreiter/micropython,vitiral/micropython,dinau/micropython,kostyll/micropython,Vogtinator/micropython,EcmaXp/micropython,feilongfl/micropython,blmorris/micropython,drrk/micropython,neilh10/micropython,kerneltask/micropython,adafruit/circuitpython,ryannathans/micropython,ahotam/micropython,hosaka/micropython,EcmaXp/micropython,hosaka/micropython,xuxiaoxin/micropython,kostyll/micropython,ruffy91/micropython,tdautc19841202/micropython,xuxiaoxin/micropython,cwyark/micropython,omtinez/micropython,warner83/micropython,warner83/micropython,mgyenik/micropython,mianos/micropython,lowRISC/micropython,skybird6672/micropython,tralamazza/micropython,rubencabrera/micropython,drrk/micropython,dinau/micropython,SHA2017-badge/micropython-esp32,adamkh/micropython,noahwilliamsson/micropython,noahchense/micropython,bvernoux/micropython,blazewicz/micropython,supergis/micropython,trezor/micropython,xuxiaoxin/micropython,rubencabrera/micropython,noahchense/micropython,tobbad/micropython,dxxb/micropython,adafruit/circuitpython,jimkmc/micropython,xhat/micropython,firstval/micropython,skybird6672/micropython,dxxb/micropython,heisewangluo/micropython,mhoffma/micropython,noahwilliamsson/micropython,misterdanb/micropython,infinnovation/micropython,micropython/micropython-esp32,ryannathans/micropython,slzatz/micropython,blazewicz/micropython,xyb/micropython,ernesto-g/micropython,deshipu/micropython,hiway/micropython,alex-robbins/micropython,puuu/micropython,ceramos/micropython,misterdanb/micropython,pozetroninc/micropython,methoxid/micropystat,martinribelotta/micropython,HenrikSolver/micropython,SHA2017-badge/micropython-esp32,ganshun666/micropython,alex-robbins/micropython,MrSurly/micropython,noahchense/micropython,dmazzella/micropython,lowRISC/micropython,vitiral/micropython,cwyark/micropython,deshipu/micropython,TDAbboud/micropython,torwag/micropython,ruffy91/micropython,henriknelson/micropython,noahwilliamsson/micropython,jlillest/micropython,infinnovation/micropython,jlillest/micropython,heisewangluo/micropython,mpalomer/micropython,blazewicz/micropython,hiway/micropython,slzatz/micropython,dmazzella/micropython,rubencabrera/micropython,selste/micropython,vriera/micropython,utopiaprince/micropython,lbattraw/micropython,adafruit/micropython,vriera/micropython,xhat/micropython,drrk/micropython,pramasoul/micropython,Vogtinator/micropython