unix/Makefile: Make install more compatible (BSD, etc.).
unix/Makefile: Make install more compatible (BSD, etc.).

The current install command uses the flag -D which is specific to the
install command from GNU coreutils, but isn't available for the BSD
version. This solution uses the -d flag which should be commonly
available to create the target directory. Afterwards the target files
are installed to this directory seperately.

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