dist/tools: include uname check for FreeBSD in genconfigheader
dist/tools: include uname check for FreeBSD in genconfigheader

Analog to Darwin set `MD5SUM` to `md5 -r`.

josephnoir/RIOT,adrianghc/RIOT,backenklee/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,Hyungsin/RIOT-OS,ks156/RIOT,kbumsik/RIOT,kaleb-himes/RIOT,immesys/RiSyn,Ell-i/RIOT,TobiasFredersdorf/RIOT,authmillenon/RIOT,syin2/RIOT,jasonatran/RIOT,dailab/RIOT,avmelnikoff/RIOT,josephnoir/RIOT,kerneltask/RIOT,biboc/RIOT,yogo1212/RIOT,plushvoxel/RIOT,kaleb-himes/RIOT,alignan/RIOT,BytesGalore/RIOT,jbeyerstedt/RIOT-OTA-update,smlng/RIOT,katezilla/RIOT,gebart/RIOT,LudwigKnuepfer/RIOT,gautric/RIOT,aeneby/RIOT,adrianghc/RIOT,kerneltask/RIOT,TobiasFredersdorf/RIOT,mtausig/RIOT,kb2ma/RIOT,smlng/RIOT,neumodisch/RIOT,LudwigOrtmann/RIOT,gautric/RIOT,kb2ma/RIOT,backenklee/RIOT,rfuentess/RIOT,jbeyerstedt/RIOT-OTA-update,Ell-i/RIOT,LudwigKnuepfer/RIOT,cladmi/RIOT,OlegHahm/RIOT,TobiasFredersdorf/RIOT,Hyungsin/RIOT-OS,mfrey/RIOT,RIOT-OS/RIOT,adrianghc/RIOT,basilfx/RIOT,alignan/RIOT,OTAkeys/RIOT,A-Paul/RIOT,TobiasFredersdorf/RIOT,x3ro/RIOT,cladmi/RIOT,cladmi/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,backenklee/RIOT,lazytech-org/RIOT,kYc0o/RIOT,immesys/RiSyn,A-Paul/RIOT,tfar/RIOT,LudwigOrtmann/RIOT,rfuentess/RIOT,kb2ma/RIOT,gebart/RIOT,kb2ma/RIOT,authmillenon/RIOT,dkm/RIOT,ks156/RIOT,thomaseichinger/RIOT,neiljay/RIOT,LudwigOrtmann/RIOT,plushvoxel/RIOT,neumodisch/RIOT,cladmi/RIOT,syin2/RIOT,jbeyerstedt/RIOT-OTA-update,dailab/RIOT,katezilla/RIOT,kYc0o/RIOT,gebart/RIOT,beurdouche/RIOT,katezilla/RIOT,roberthartung/RIOT,jasonatran/RIOT,kb2ma/RIOT,d00616/RIOT,OTAkeys/RIOT,adrianghc/RIOT,jfischer-phytec-iot/RIOT,lazytech-org/RIOT,thomaseichinger/RIOT,toonst/RIOT,smlng/RIOT,BytesGalore/RIOT,BytesGalore/RIOT,syin2/RIOT,basilfx/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,immesys/RiSyn,yogo1212/RIOT,rfuentess/RIOT,kaspar030/RIOT,ks156/RIOT,mfrey/RIOT,beurdouche/RIOT,adjih/RIOT,x3ro/RIOT,TobiasFredersdorf/RIOT,LudwigKnuepfer/RIOT,BytesGalore/RIOT,kbumsik/RIOT,avmelnikoff/RIOT,LudwigOrtmann/RIOT,thomaseichinger/RIOT,dailab/RIOT,A-Paul/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,mfrey/RIOT,roberthartung/RIOT,OlegHahm/RIOT,roberthartung/RIOT,jfischer-phytec-iot/RIOT,aeneby/RIOT,kaspar030/RIOT,dkm/RIOT,immesys/RiSyn,kbumsik/RIOT,basilfx/RIOT,neumodisch/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,authmillenon/RIOT,kYc0o/RIOT,syin2/RIOT,backenklee/RIOT,jfischer-phytec-iot/RIOT,authmillenon/RIOT,miri64/RIOT,immesys/RiSyn,roberthartung/RIOT,d00616/RIOT,miri64/RIOT,hamilton-mote/RIOT-OS,Ell-i/RIOT,yogo1212/RIOT,LudwigOrtmann/RIOT,d00616/RIOT,RIOT-OS/RIOT,biboc/RIOT,mtausig/RIOT,biboc/RIOT,d00616/RIOT,josephnoir/RIOT,dkm/RIOT,OTAkeys/RIOT,ks156/RIOT,tfar/RIOT,neumodisch/RIOT,Josar/RIOT,dkm/RIOT,kaspar030/RIOT,A-Paul/RIOT,backenklee/RIOT,toonst/RIOT,neiljay/RIOT,neumodisch/RIOT,OlegHahm/RIOT,gebart/RIOT,yogo1212/RIOT,Josar/RIOT,rfuentess/RIOT,avmelnikoff/RIOT,gautric/RIOT,beurdouche/RIOT,x3ro/RIOT,ant9000/RIOT,OTAkeys/RIOT,kerneltask/RIOT,cladmi/RIOT,gautric/RIOT,d00616/RIOT,aeneby/RIOT,Josar/RIOT,josephnoir/RIOT,jbeyerstedt/RIOT-OTA-update,dkm/RIOT,OlegHahm/RIOT,neiljay/RIOT,miri64/RIOT,Josar/RIOT,lazytech-org/RIOT,Hyungsin/RIOT-OS,A-Paul/RIOT,adjih/RIOT,ant9000/RIOT,x3ro/RIOT,thomaseichinger/RIOT,gebart/RIOT,ks156/RIOT,katezilla/RIOT,lazytech-org/RIOT,Hyungsin/RIOT-OS,basilfx/RIOT,kYc0o/RIOT,Ell-i/RIOT,avmelnikoff/RIOT,aeneby/RIOT,jbeyerstedt/RIOT-OTA-update,jfischer-phytec-iot/RIOT,alignan/RIOT,ant9000/RIOT,mtausig/RIOT,jasonatran/RIOT,kerneltask/RIOT,kbumsik/RIOT,hamilton-mote/RIOT-OS,basilfx/RIOT,beurdouche/RIOT,mtausig/RIOT,BytesGalore/RIOT,avmelnikoff/RIOT,adjih/RIOT,adrianghc/RIOT,kaspar030/RIOT,LudwigOrtmann/RIOT,plushvoxel/RIOT,toonst/RIOT,Josar/RIOT,OlegHahm/RIOT,toonst/RIOT,smlng/RIOT,adjih/RIOT,katezilla/RIOT,kaleb-himes/RIOT,toonst/RIOT,dailab/RIOT,alignan/RIOT,jasonatran/RIOT,adjih/RIOT,yogo1212/RIOT,Ell-i/RIOT,jfischer-phytec-iot/RIOT,kaleb-himes/RIOT,LudwigKnuepfer/RIOT,tfar/RIOT,kbumsik/RIOT,neumodisch/RIOT,lazytech-org/RIOT,LudwigKnuepfer/RIOT,alignan/RIOT,rfuentess/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,authmillenon/RIOT,kYc0o/RIOT,ant9000/RIOT,immesys/RiSyn,plushvoxel/RIOT,RIOT-OS/RIOT,biboc/RIOT,smlng/RIOT,hamilton-mote/RIOT-OS,tfar/RIOT,gautric/RIOT,beurdouche/RIOT,mtausig/RIOT,hamilton-mote/RIOT-OS,miri64/RIOT,mfrey/RIOT,neiljay/RIOT,tfar/RIOT,plushvoxel/RIOT,mfrey/RIOT,neiljay/RIOT,yogo1212/RIOT,roberthartung/RIOT,aeneby/RIOT,kaspar030/RIOT,thomaseichinger/RIOT,ant9000/RIOT,dailab/RIOT,hamilton-mote/RIOT-OS,jasonatran/RIOT,d00616/RIOT,OTAkeys/RIOT,Hyungsin/RIOT-OS,biboc/RIOT,kaleb-himes/RIOT,syin2/RIOT,x3ro/RIOT,kerneltask/RIOT,miri64/RIOT