unix/mpthreadport: Adjust minimum thread stack, and stack limit check.
unix/mpthreadport: Adjust minimum thread stack, and stack limit check.

The minimum thread stack size is set by pthreads (16k bytes) so we must
use that value for our minimum.  The stack limit check is also adjusted
to work correctly for 32-bit builds.

MrSurly/micropython-esp32,infinnovation/micropython,pozetroninc/micropython,jmarcelino/pycom-micropython,adafruit/micropython,lowRISC/micropython,MrSurly/micropython,blazewicz/micropython,tuc-osg/micropython,alex-march/micropython,oopy/micropython,chrisdearman/micropython,TDAbboud/micropython,henriknelson/micropython,AriZuu/micropython,micropython/micropython-esp32,ryannathans/micropython,micropython/micropython-esp32,oopy/micropython,alex-march/micropython,kerneltask/micropython,pozetroninc/micropython,alex-robbins/micropython,swegener/micropython,blazewicz/micropython,matthewelse/micropython,infinnovation/micropython,tobbad/micropython,Peetz0r/micropython-esp32,HenrikSolver/micropython,mhoffma/micropython,MrSurly/micropython,adafruit/circuitpython,tralamazza/micropython,pramasoul/micropython,pramasoul/micropython,alex-robbins/micropython,MrSurly/micropython-esp32,lowRISC/micropython,turbinenreiter/micropython,matthewelse/micropython,tuc-osg/micropython,Peetz0r/micropython-esp32,selste/micropython,HenrikSolver/micropython,deshipu/micropython,pfalcon/micropython,Timmenem/micropython,jmarcelino/pycom-micropython,alex-march/micropython,bvernoux/micropython,MrSurly/micropython,pramasoul/micropython,deshipu/micropython,matthewelse/micropython,turbinenreiter/micropython,MrSurly/micropython,alex-robbins/micropython,tuc-osg/micropython,infinnovation/micropython,selste/micropython,pfalcon/micropython,PappaPeppar/micropython,trezor/micropython,adafruit/micropython,tobbad/micropython,pramasoul/micropython,matthewelse/micropython,selste/micropython,ganshun666/micropython,ganshun666/micropython,deshipu/micropython,selste/micropython,hosaka/micropython,HenrikSolver/micropython,redbear/micropython,dxxb/micropython,hiway/micropython,TDAbboud/micropython,redbear/micropython,hiway/micropython,puuu/micropython,jmarcelino/pycom-micropython,puuu/micropython,tobbad/micropython,micropython/micropython-esp32,MrSurly/micropython-esp32,oopy/micropython,dxxb/micropython,Timmenem/micropython,dmazzella/micropython,blazewicz/micropython,puuu/micropython,PappaPeppar/micropython,kerneltask/micropython,Timmenem/micropython,alex-march/micropython,infinnovation/micropython,ryannathans/micropython,mhoffma/micropython,PappaPeppar/micropython,chrisdearman/micropython,turbinenreiter/micropython,SHA2017-badge/micropython-esp32,hosaka/micropython,trezor/micropython,ganshun666/micropython,ryannathans/micropython,torwag/micropython,infinnovation/micropython,pfalcon/micropython,kerneltask/micropython,ganshun666/micropython,Peetz0r/micropython-esp32,Timmenem/micropython,tralamazza/micropython,henriknelson/micropython,turbinenreiter/micropython,redbear/micropython,Peetz0r/micropython-esp32,Peetz0r/micropython-esp32,hosaka/micropython,alex-robbins/micropython,kerneltask/micropython,pozetroninc/micropython,bvernoux/micropython,mhoffma/micropython,adafruit/circuitpython,selste/micropython,oopy/micropython,jmarcelino/pycom-micropython,jmarcelino/pycom-micropython,micropython/micropython-esp32,matthewelse/micropython,torwag/micropython,cwyark/micropython,PappaPeppar/micropython,alex-march/micropython,dxxb/micropython,bvernoux/micropython,cwyark/micropython,pramasoul/micropython,lowRISC/micropython,hosaka/micropython,SHA2017-badge/micropython-esp32,adafruit/circuitpython,AriZuu/micropython,hiway/micropython,matthewelse/micropython,toolmacher/micropython,adafruit/circuitpython,chrisdearman/micropython,pozetroninc/micropython,hosaka/micropython,micropython/micropython-esp32,cwyark/micropython,ryannathans/micropython,dmazzella/micropython,trezor/micropython,TDAbboud/micropython,puuu/micropython,chrisdearman/micropython,chrisdearman/micropython,toolmacher/micropython,pfalcon/micropython,PappaPeppar/micropython,AriZuu/micropython,HenrikSolver/micropython,torwag/micropython,cwyark/micropython,dxxb/micropython,henriknelson/micropython,trezor/micropython,dxxb/micropython,ryannathans/micropython,tuc-osg/micropython,adafruit/micropython,hiway/micropython,MrSurly/micropython-esp32,henriknelson/micropython,toolmacher/micropython,kerneltask/micropython,MrSurly/micropython-esp32,turbinenreiter/micropython,deshipu/micropython,swegener/micropython,henriknelson/micropython,Timmenem/micropython,tobbad/micropython,swegener/micropython,MrSurly/micropython,blazewicz/micropython,toolmacher/micropython,HenrikSolver/micropython,toolmacher/micropython,cwyark/micropython,TDAbboud/micropython,tralamazza/micropython,SHA2017-badge/micropython-esp32,deshipu/micropython,swegener/micropython,ganshun666/micropython,mhoffma/micropython,redbear/micropython,blazewicz/micropython,adafruit/circuitpython,TDAbboud/micropython,adafruit/micropython,SHA2017-badge/micropython-esp32,tobbad/micropython,AriZuu/micropython,lowRISC/micropython,trezor/micropython,dmazzella/micropython,AriZuu/micropython,pfalcon/micropython,torwag/micropython,puuu/micropython,pozetroninc/micropython,tralamazza/micropython,hiway/micropython,adafruit/circuitpython,bvernoux/micropython,torwag/micropython,adafruit/micropython,SHA2017-badge/micropython-esp32,mhoffma/micropython,tuc-osg/micropython,redbear/micropython,bvernoux/micropython,swegener/micropython,oopy/micropython,lowRISC/micropython,alex-robbins/micropython,dmazzella/micropython