make: supply `-j` on `buildtest`
make: supply `-j` on `buildtest`

We support `make -j` for a while now. `make buildtest` takes ages to
finish. So just supply `-j` on buildtest.

kaleb-himes/RIOT,jhollister/RIOT,locicontrols/RIOT,herrfz/RIOT-old,1blankz7/RIOT,Lotterleben/RIOT,arvindpdmn/RIOT,benoit-canet/RIOT,altairpearl/RIOT,mfrey/RIOT,robixnai/RIOT,rfuentess/RIOT,ntrtrung/RIOT,rfswarm/RIOT,biboc/RIOT,phiros/RIOT,rfswarm/RIOT,binarylemon/RIOT,gebart/RIOT,shady33/RIOT,OlegHahm/RIOT,LudwigOrtmann/RIOT,DipSwitch/RIOT,miri64/RIOT,kaleb-himes/RIOT,ant9000/RIOT,kbumsik/RIOT,MohmadAyman/RIOT,herrfz/RIOT,EmuxEvans/RIOT,abkam07/RIOT,centurysys/RIOT,openkosmosorg/RIOT,latsku/RIOT,ros2/ros2_embedded_riot,ros2/ros2_embedded_riot,rajma996/RIOT,A-Paul/RIOT,PSHIVANI/Riot-Code,chris-wood/RIOT,Hyungsin/RIOT-OS,arvindpdmn/RIOT,robixnai/RIOT,fnack/RIOT,tdautc19841202/RIOT,JensErdmann/RIOT,abp719/RIOT,ThanhVic/RIOT,gbarnett/RIOT,rfswarm2/RIOT,backenklee/RIOT,asanka-code/RIOT,AnonMall/RIOT,thomaseichinger/RIOT,MarkXYang/RIOT,gbarnett/RIOT,adrianghc/RIOT,miri64/RIOT,MohmadAyman/RIOT,msolters/RIOT,lazytech-org/RIOT,Ell-i/RIOT,rousselk/RIOT,Lexandro92/RIOT-CoAP,RBartz/RIOT,patkan/RIOT,automote/RIOT,mziegert/RIOT,neiljay/RIOT,beurdouche/RIOT,authmillenon/RIOT,Yonezawa-T2/RIOT,benoit-canet/RIOT,ximus/RIOT,dailab/RIOT,patkan/RIOT,l3nko/RIOT,luciotorre/RIOT,malosek/RIOT,basilfx/RIOT,DipSwitch/RIOT,zhuoshuguo/RIOT,marcosalm/RIOT,ros2/ros2_embedded_riot,rfswarm2/RIOT,FrancescoErmini/RIOT,adjih/RIOT,immesys/RiSyn,kYc0o/RIOT,alignan/RIOT,avmelnikoff/RIOT,smlng/RIOT,shady33/RIOT,miri64/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,kerneltask/RIOT,Josar/RIOT,d00616/RIOT,chris-wood/RIOT,alex1818/RIOT,Lexandro92/RIOT-CoAP,kerneltask/RIOT,khhhh/RIOT,daniel-k/RIOT,jhollister/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,jferreir/RIOT,beurdouche/RIOT,openkosmosorg/RIOT,binarylemon/RIOT,latsku/RIOT,emmanuelsearch/RIOT,ks156/RIOT,MohmadAyman/RIOT,A-Paul/RIOT,centurysys/RIOT,Hyungsin/RIOT-OS,BytesGalore/PetersRIOT,ntrtrung/RIOT,TobiasFredersdorf/RIOT,Osblouf/RIOT,EmuxEvans/RIOT,rousselk/RIOT,ximus/RIOT,chris-wood/RIOT,Josar/RIOT,RBartz/RIOT,dhruvvyas90/RIOT,jasonatran/RIOT,daniel-k/RIOT,BytesGalore/PetersRIOT,rfswarm/RIOT,thomaseichinger/RIOT,yogo1212/RIOT,luciotorre/RIOT,Darredevil/RIOT,rajma996/RIOT,abp719/RIOT,nsol-nmsu/RIOT,chris-wood/RIOT,Darredevil/RIOT,locicontrols/RIOT,robixnai/RIOT,alignan/RIOT,brettswann/RIOT,Lexandro92/RIOT-CoAP,mziegert/RIOT,phiros/RIOT,jfischer-phytec-iot/RIOT,changbiao/RIOT,koenning/RIOT,cladmi/RIOT,jremmert-phytec-iot/RIOT,stevenj/RIOT,spium/IoT-RIOT,tdautc19841202/RIOT,Yonezawa-T2/RIOT,kaleb-himes/RIOT,PSHIVANI/Riot-Code,rousselk/RIOT,Darredevil/RIOT,BytesGalore/RIOT,haoyangyu/RIOT,neiljay/RIOT,khhhh/RIOT,abp719/RIOT,centurysys/RIOT,hamilton-mote/RIOT-OS,changbiao/RIOT,gbarnett/RIOT,sgso/RIOT,phiros/RIOT,zhuoshuguo/RIOT,MohmadAyman/RIOT,roberthartung/RIOT,altairpearl/RIOT,OlegHahm/RIOT,ntrtrung/RIOT,changbiao/RIOT,jasonatran/RIOT,rakendrathapa/RIOT,tfar/RIOT,latsku/RIOT,ThanhVic/RIOT,ros2/ros2_embedded_riot,FrancescoErmini/RIOT,MonsterCode8000/RIOT,aeneby/RIOT,aeneby/RIOT,toonst/RIOT,lebrush/RIOT,stevenj/RIOT,locicontrols/RIOT,lebrush/RIOT,fnack/RIOT,jremmert-phytec-iot/RIOT,fnack/RIOT,ros2/ros2_embedded_riot,altairpearl/RIOT,rajma996/RIOT,kaleb-himes/RIOT,syin2/RIOT,luciotorre/RIOT,koenning/RIOT,RubikonAlpha/RIOT,automote/RIOT,LudwigOrtmann/RIOT,ks156/RIOT,gautric/RIOT,gautric/RIOT,jferreir/RIOT,adjih/RIOT,latsku/RIOT,EmuxEvans/RIOT,l3nko/RIOT,openkosmosorg/RIOT,EmuxEvans/RIOT,plushvoxel/RIOT,asanka-code/RIOT,Lotterleben/RIOT,OTAkeys/RIOT,Lexandro92/RIOT-CoAP,sumanpanchal/RIOT,smlng/RIOT,marcosalm/RIOT,Lotterleben/RIOT,luciotorre/RIOT,MohmadAyman/RIOT,gbarnett/RIOT,RubikonAlpha/RIOT,herrfz/RIOT,patkan/RIOT,brettswann/RIOT,toonst/RIOT,adjih/RIOT,adrianghc/RIOT,zhuoshuguo/RIOT,marcosalm/RIOT,watr-li/RIOT,rakendrathapa/RIOT,watr-li/RIOT,shady33/RIOT,syin2/RIOT,marcosalm/RIOT,alignan/RIOT,basilfx/RIOT,hamilton-mote/RIOT-OS,adjih/RIOT,watr-li/RIOT,kYc0o/RIOT,toonst/RIOT,l3nko/RIOT,chris-wood/RIOT,zhuoshuguo/RIOT,ximus/RIOT,yogo1212/RIOT,kushalsingh007/RIOT,dailab/RIOT,EmuxEvans/RIOT,RBartz/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,josephnoir/RIOT,lebrush/RIOT,binarylemon/RIOT,latsku/RIOT,spium/IoT-RIOT,LudwigKnuepfer/RIOT,DipSwitch/RIOT,Osblouf/RIOT,hamilton-mote/RIOT-OS,alex1818/RIOT,gebart/RIOT,immesys/RiSyn,Lexandro92/RIOT-CoAP,roberthartung/RIOT,koenning/RIOT,herrfz/RIOT,arvindpdmn/RIOT,A-Paul/RIOT,aeneby/RIOT,mziegert/RIOT,abp719/RIOT,herrfz/RIOT,rakendrathapa/RIOT,kerneltask/RIOT,syin2/RIOT,alex1818/RIOT,katezilla/RIOT,cladmi/RIOT,rfswarm/RIOT,katezilla/RIOT,syin2/RIOT,malosek/RIOT,d00616/RIOT,alignan/RIOT,watr-li/RIOT,RIOT-OS/RIOT,haoyangyu/RIOT,gebart/RIOT,katezilla/RIOT,x3ro/RIOT,authmillenon/RIOT,MonsterCode8000/RIOT,Ell-i/RIOT,alex1818/RIOT,l3nko/RIOT,miri64/RIOT,alignan/RIOT,openkosmosorg/RIOT,latsku/RIOT,rfswarm2/RIOT,Lexandro92/RIOT-CoAP,centurysys/RIOT,gautric/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,abkam07/RIOT,roberthartung/RIOT,d00616/RIOT,tfar/RIOT,attdona/RIOT,thomaseichinger/RIOT,altairpearl/RIOT,stevenj/RIOT,tdautc19841202/RIOT,immesys/RiSyn,Yonezawa-T2/RIOT,abkam07/RIOT,ximus/RIOT,lebrush/RIOT,lazytech-org/RIOT,backenklee/RIOT,rousselk/RIOT,miri64/RIOT,spium/IoT-RIOT,asanka-code/RIOT,herrfz/RIOT-old,malosek/RIOT,MonsterCode8000/RIOT,FrancescoErmini/RIOT,biboc/RIOT,neiljay/RIOT,1blankz7/RIOT,rfuentess/RIOT,FrancescoErmini/RIOT,tdautc19841202/RIOT,ant9000/RIOT,attdona/RIOT,ant9000/RIOT,msolters/RIOT,changbiao/RIOT,nsol-nmsu/RIOT,tfar/RIOT,mtausig/RIOT,ks156/RIOT,neumodisch/RIOT,MohmadAyman/RIOT,kbumsik/RIOT,marcosalm/RIOT,tdautc19841202/RIOT,khhhh/RIOT,shady33/RIOT,attdona/RIOT,rakendrathapa/RIOT,Josar/RIOT,hamilton-mote/RIOT-OS,wentaoshang/RIOT,sumanpanchal/RIOT,jferreir/RIOT,rfswarm2/RIOT,luciotorre/RIOT,thomaseichinger/RIOT,avmelnikoff/RIOT,TobiasFredersdorf/RIOT,nsol-nmsu/RIOT,arvindpdmn/RIOT,asanka-code/RIOT,bartfaizoltan/RIOT,spium/IoT-RIOT,bartfaizoltan/RIOT,jhollister/RIOT,JensErdmann/RIOT,DipSwitch/RIOT,neiljay/RIOT,kb2ma/RIOT,Lotterleben/RIOT,immesys/RiSyn,jferreir/RIOT,kushalsingh007/RIOT,binarylemon/RIOT,malosek/RIOT,ant9000/RIOT,jbeyerstedt/RIOT-OTA-update,locicontrols/RIOT,ThanhVic/RIOT,Hyungsin/RIOT-OS,emmanuelsearch/RIOT,TobiasFredersdorf/RIOT,gautric/RIOT,benoit-canet/RIOT,mfrey/RIOT,openkosmosorg/RIOT,jremmert-phytec-iot/RIOT,Lotterleben/RIOT,sgso/RIOT,neumodisch/RIOT,toonst/RIOT,kbumsik/RIOT,biboc/RIOT,nsol-nmsu/RIOT,arvindpdmn/RIOT,Yonezawa-T2/RIOT,kerneltask/RIOT,RubikonAlpha/RIOT,thiagohd/RIOT,mtausig/RIOT,malosek/RIOT,lazytech-org/RIOT,BytesGalore/PetersRIOT,sumanpanchal/RIOT,BytesGalore/PetersRIOT,AnonMall/RIOT,kYc0o/RIOT,jasonatran/RIOT,RBartz/RIOT,dailab/RIOT,kushalsingh007/RIOT,lazytech-org/RIOT,daniel-k/RIOT,locicontrols/RIOT,jremmert-phytec-iot/RIOT,Lotterleben/RIOT,nsol-nmsu/RIOT,brettswann/RIOT,tfar/RIOT,kbumsik/RIOT,katezilla/RIOT,rfswarm/RIOT,khhhh/RIOT,herrfz/RIOT,adrianghc/RIOT,neumodisch/RIOT,daniel-k/RIOT,wentaoshang/RIOT,binarylemon/RIOT,RubikonAlpha/RIOT,bartfaizoltan/RIOT,MarkXYang/RIOT,herrfz/RIOT-old,ThanhVic/RIOT,jremmert-phytec-iot/RIOT,avmelnikoff/RIOT,immesys/RiSyn,Yonezawa-T2/RIOT,wentaoshang/RIOT,abkam07/RIOT,AnonMall/RIOT,1blankz7/RIOT,mziegert/RIOT,kbumsik/RIOT,asanka-code/RIOT,kaspar030/RIOT,neumodisch/RIOT,plushvoxel/RIOT,authmillenon/RIOT,spium/IoT-RIOT,gebart/RIOT,gbarnett/RIOT,biboc/RIOT,FrancescoErmini/RIOT,arvindpdmn/RIOT,1blankz7/RIOT,sumanpanchal/RIOT,dhruvvyas90/RIOT,dhruvvyas90/RIOT,authmillenon/RIOT,dkm/RIOT,rousselk/RIOT,dhruvvyas90/RIOT,ThanhVic/RIOT,LudwigOrtmann/RIOT,zhuoshuguo/RIOT,JensErdmann/RIOT,lebrush/RIOT,rajma996/RIOT,koenning/RIOT,plushvoxel/RIOT,neumodisch/RIOT,smlng/RIOT,1blankz7/RIOT,dhruvvyas90/RIOT,LudwigKnuepfer/RIOT,Ell-i/RIOT,jfischer-phytec-iot/RIOT,sgso/RIOT,rfuentess/RIOT,LudwigOrtmann/RIOT,kaspar030/RIOT,authmillenon/RIOT,plushvoxel/RIOT,mtausig/RIOT,jferreir/RIOT,basilfx/RIOT,kYc0o/RIOT,mfrey/RIOT,wentaoshang/RIOT,zhuoshuguo/RIOT,josephnoir/RIOT,abkam07/RIOT,brettswann/RIOT,josephnoir/RIOT,tdautc19841202/RIOT,dailab/RIOT,BytesGalore/RIOT,kushalsingh007/RIOT,thiagohd/RIOT,aeneby/RIOT,TobiasFredersdorf/RIOT,altairpearl/RIOT,ks156/RIOT,mfrey/RIOT,RBartz/RIOT,lazytech-org/RIOT,roberthartung/RIOT,A-Paul/RIOT,wentaoshang/RIOT,haoyangyu/RIOT,immesys/RiSyn,openkosmosorg/RIOT,rfswarm/RIOT,LudwigKnuepfer/RIOT,d00616/RIOT,brettswann/RIOT,authmillenon/RIOT,attdona/RIOT,luciotorre/RIOT,Osblouf/RIOT,kaspar030/RIOT,d00616/RIOT,benoit-canet/RIOT,rajma996/RIOT,Darredevil/RIOT,jremmert-phytec-iot/RIOT,thiagohd/RIOT,Hyungsin/RIOT-OS,OTAkeys/RIOT,spium/IoT-RIOT,haoyangyu/RIOT,MarkXYang/RIOT,dailab/RIOT,l3nko/RIOT,MonsterCode8000/RIOT,automote/RIOT,herrfz/RIOT-old,DipSwitch/RIOT,hamilton-mote/RIOT-OS,robixnai/RIOT,centurysys/RIOT,RIOT-OS/RIOT,benoit-canet/RIOT,rfuentess/RIOT,cladmi/RIOT,robixnai/RIOT,herrfz/RIOT,lebrush/RIOT,1blankz7/RIOT,jfischer-phytec-iot/RIOT,adjih/RIOT,fnack/RIOT,kYc0o/RIOT,BytesGalore/PetersRIOT,dkm/RIOT,jhollister/RIOT,Josar/RIOT,asanka-code/RIOT,patkan/RIOT,kb2ma/RIOT,mziegert/RIOT,AnonMall/RIOT,Darredevil/RIOT,bartfaizoltan/RIOT,changbiao/RIOT,ros2/ros2_embedded_riot,A-Paul/RIOT,alex1818/RIOT,jbeyerstedt/RIOT-OTA-update,LudwigKnuepfer/RIOT,kaspar030/RIOT,mtausig/RIOT,adrianghc/RIOT,beurdouche/RIOT,EmuxEvans/RIOT,gbarnett/RIOT,TobiasFredersdorf/RIOT,BytesGalore/PetersRIOT,locicontrols/RIOT,syin2/RIOT,dhruvvyas90/RIOT,kaspar030/RIOT,rakendrathapa/RIOT,beurdouche/RIOT,abkam07/RIOT,automote/RIOT,x3ro/RIOT,ntrtrung/RIOT,kb2ma/RIOT,jhollister/RIOT,d00616/RIOT,kb2ma/RIOT,tfar/RIOT,stevenj/RIOT,chris-wood/RIOT,x3ro/RIOT,DipSwitch/RIOT,beurdouche/RIOT,kerneltask/RIOT,FrancescoErmini/RIOT,haoyangyu/RIOT,patkan/RIOT,l3nko/RIOT,kushalsingh007/RIOT,smlng/RIOT,watr-li/RIOT,PSHIVANI/Riot-Code,Darredevil/RIOT,phiros/RIOT,wentaoshang/RIOT,daniel-k/RIOT,Yonezawa-T2/RIOT,LudwigKnuepfer/RIOT,stevenj/RIOT,cladmi/RIOT,jasonatran/RIOT,emmanuelsearch/RIOT,ks156/RIOT,RBartz/RIOT,herrfz/RIOT-old,daniel-k/RIOT,thiagohd/RIOT,robixnai/RIOT,Osblouf/RIOT,benoit-canet/RIOT,watr-li/RIOT,dkm/RIOT,attdona/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,rajma996/RIOT,malosek/RIOT,rousselk/RIOT,MarkXYang/RIOT,kushalsingh007/RIOT,backenklee/RIOT,sumanpanchal/RIOT,jbeyerstedt/RIOT-OTA-update,adrianghc/RIOT,khhhh/RIOT,LudwigOrtmann/RIOT,jferreir/RIOT,attdona/RIOT,OTAkeys/RIOT,dkm/RIOT,yogo1212/RIOT,thiagohd/RIOT,PSHIVANI/Riot-Code,JensErdmann/RIOT,patkan/RIOT,ant9000/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,josephnoir/RIOT,basilfx/RIOT,Hyungsin/RIOT-OS,MonsterCode8000/RIOT,msolters/RIOT,JensErdmann/RIOT,BytesGalore/RIOT,thomaseichinger/RIOT,ntrtrung/RIOT,locicontrols/RIOT,marcosalm/RIOT,fnack/RIOT,phiros/RIOT,jfischer-phytec-iot/RIOT,ximus/RIOT,sgso/RIOT,aeneby/RIOT,ThanhVic/RIOT,brettswann/RIOT,cladmi/RIOT,LudwigOrtmann/RIOT,abp719/RIOT,koenning/RIOT,Ell-i/RIOT,BytesGalore/PetersRIOT,neumodisch/RIOT,BytesGalore/RIOT,yogo1212/RIOT,kaleb-himes/RIOT,jhollister/RIOT,bartfaizoltan/RIOT,basilfx/RIOT,gautric/RIOT,bartfaizoltan/RIOT,changbiao/RIOT,koenning/RIOT,Osblouf/RIOT,katezilla/RIOT,automote/RIOT,BytesGalore/RIOT,rfswarm2/RIOT,shady33/RIOT,emmanuelsearch/RIOT,ntrtrung/RIOT,roberthartung/RIOT,jbeyerstedt/RIOT-OTA-update,fnack/RIOT,toonst/RIOT,Lotterleben/RIOT,AnonMall/RIOT,avmelnikoff/RIOT,phiros/RIOT,avmelnikoff/RIOT,alex1818/RIOT,jbeyerstedt/RIOT-OTA-update,shady33/RIOT,abp719/RIOT,sumanpanchal/RIOT,automote/RIOT,OlegHahm/RIOT,plushvoxel/RIOT,emmanuelsearch/RIOT,msolters/RIOT,AnonMall/RIOT,gebart/RIOT,haoyangyu/RIOT,stevenj/RIOT,mziegert/RIOT,backenklee/RIOT,OlegHahm/RIOT,MarkXYang/RIOT,thiagohd/RIOT,OlegHahm/RIOT,backenklee/RIOT,RubikonAlpha/RIOT,ros2/ros2_embedded_riot,sgso/RIOT,emmanuelsearch/RIOT,altairpearl/RIOT,khhhh/RIOT,RubikonAlpha/RIOT,Josar/RIOT,MarkXYang/RIOT,rakendrathapa/RIOT,msolters/RIOT,yogo1212/RIOT,centurysys/RIOT,mfrey/RIOT,Osblouf/RIOT,RIOT-OS/RIOT,rfswarm2/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,neiljay/RIOT,OTAkeys/RIOT,dkm/RIOT,x3ro/RIOT,jfischer-phytec-iot/RIOT,yogo1212/RIOT,biboc/RIOT,msolters/RIOT,ximus/RIOT,rfuentess/RIOT,MonsterCode8000/RIOT,PSHIVANI/Riot-Code,mtausig/RIOT,x3ro/RIOT,binarylemon/RIOT,smlng/RIOT,jasonatran/RIOT,Ell-i/RIOT,kb2ma/RIOT,PSHIVANI/Riot-Code,sgso/RIOT,JensErdmann/RIOT