cpu/stm32f4: added custom GPIO_UNDEF define
cpu/stm32f4: added custom GPIO_UNDEF define

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