Add recursive header inclusion guard for sigtools header.
Add recursive header inclusion guard for sigtools header.

gdooper/scipy,maciejkula/scipy,pschella/scipy,rmcgibbo/scipy,witcxc/scipy,nonhermitian/scipy,raoulbq/scipy,arokem/scipy,ChanderG/scipy,chatcannon/scipy,rgommers/scipy,zerothi/scipy,sriki18/scipy,surhudm/scipy,chatcannon/scipy,sauliusl/scipy,minhlongdo/scipy,nvoron23/scipy,sriki18/scipy,Newman101/scipy,Gillu13/scipy,petebachant/scipy,gfyoung/scipy,zxsted/scipy,ChanderG/scipy,efiring/scipy,futurulus/scipy,sargas/scipy,scipy/scipy,WarrenWeckesser/scipy,Eric89GXL/scipy,Kamp9/scipy,mgaitan/scipy,andyfaff/scipy,WarrenWeckesser/scipy,ndchorley/scipy,ogrisel/scipy,ogrisel/scipy,njwilson23/scipy,trankmichael/scipy,haudren/scipy,jonycgn/scipy,pbrod/scipy,mortada/scipy,futurulus/scipy,ndchorley/scipy,surhudm/scipy,hainm/scipy,e-q/scipy,e-q/scipy,maniteja123/scipy,zaxliu/scipy,tylerjereddy/scipy,kalvdans/scipy,mingwpy/scipy,haudren/scipy,felipebetancur/scipy,sonnyhu/scipy,lukauskas/scipy,zxsted/scipy,endolith/scipy,haudren/scipy,vberaudi/scipy,zxsted/scipy,raoulbq/scipy,jakevdp/scipy,juliantaylor/scipy,grlee77/scipy,vanpact/scipy,jamestwebber/scipy,Shaswat27/scipy,surhudm/scipy,mortada/scipy,behzadnouri/scipy,argriffing/scipy,pschella/scipy,Dapid/scipy,futurulus/scipy,witcxc/scipy,kleskjr/scipy,fernand/scipy,jonycgn/scipy,Srisai85/scipy,chatcannon/scipy,juliantaylor/scipy,Newman101/scipy,trankmichael/scipy,vberaudi/scipy,pizzathief/scipy,matthewalbani/scipy,scipy/scipy,bkendzior/scipy,FRidh/scipy,surhudm/scipy,jamestwebber/scipy,kleskjr/scipy,mgaitan/scipy,Newman101/scipy,maniteja123/scipy,Gillu13/scipy,maniteja123/scipy,raoulbq/scipy,zerothi/scipy,mdhaber/scipy,lukauskas/scipy,kalvdans/scipy,mtrbean/scipy,mortada/scipy,chatcannon/scipy,zaxliu/scipy,jor-/scipy,Srisai85/scipy,jor-/scipy,dch312/scipy,rmcgibbo/scipy,hainm/scipy,efiring/scipy,ndchorley/scipy,lukauskas/scipy,andim/scipy,pizzathief/scipy,WillieMaddox/scipy,ogrisel/scipy,sauliusl/scipy,WillieMaddox/scipy,apbard/scipy,ChanderG/scipy,Shaswat27/scipy,mikebenfield/scipy,juliantaylor/scipy,apbard/scipy,zaxliu/scipy,sauliusl/scipy,ilayn/scipy,nvoron23/scipy,nonhermitian/scipy,mortonjt/scipy,aeklant/scipy,Shaswat27/scipy,dch312/scipy,sonnyhu/scipy,mikebenfield/scipy,nmayorov/scipy,niknow/scipy,Kamp9/scipy,niknow/scipy,larsmans/scipy,arokem/scipy,dch312/scipy,pnedunuri/scipy,Newman101/scipy,futurulus/scipy,anielsen001/scipy,sauliusl/scipy,gef756/scipy,maciejkula/scipy,Newman101/scipy,jseabold/scipy,matthew-brett/scipy,richardotis/scipy,pbrod/scipy,ndchorley/scipy,efiring/scipy,nmayorov/scipy,gfyoung/scipy,mhogg/scipy,teoliphant/scipy,larsmans/scipy,josephcslater/scipy,Stefan-Endres/scipy,giorgiop/scipy,argriffing/scipy,petebachant/scipy,scipy/scipy,nonhermitian/scipy,rgommers/scipy,rgommers/scipy,woodscn/scipy,anntzer/scipy,futurulus/scipy,zerothi/scipy,cpaulik/scipy,zerothi/scipy,person142/scipy,nvoron23/scipy,matthewalbani/scipy,josephcslater/scipy,ortylp/scipy,vhaasteren/scipy,matthewalbani/scipy,zxsted/scipy,jsilter/scipy,pnedunuri/scipy,ales-erjavec/scipy,mortonjt/scipy,WillieMaddox/scipy,juliantaylor/scipy,witcxc/scipy,niknow/scipy,nonhermitian/scipy,pbrod/scipy,anntzer/scipy,ortylp/scipy,aarchiba/scipy,teoliphant/scipy,ales-erjavec/scipy,jjhelmus/scipy,minhlongdo/scipy,chatcannon/scipy,fernand/scipy,Gillu13/scipy,felipebetancur/scipy,jonycgn/scipy,giorgiop/scipy,arokem/scipy,ales-erjavec/scipy,pyramania/scipy,Gillu13/scipy,mortada/scipy,anielsen001/scipy,ilayn/scipy,andim/scipy,vanpact/scipy,mingwpy/scipy,cpaulik/scipy,zaxliu/scipy,dominicelse/scipy,vhaasteren/scipy,sriki18/scipy,zaxliu/scipy,witcxc/scipy,efiring/scipy,ales-erjavec/scipy,mhogg/scipy,richardotis/scipy,mdhaber/scipy,aman-iitj/scipy,gdooper/scipy,haudren/scipy,vigna/scipy,woodscn/scipy,vhaasteren/scipy,vberaudi/scipy,sonnyhu/scipy,mhogg/scipy,raoulbq/scipy,rgommers/scipy,aeklant/scipy,maniteja123/scipy,pizzathief/scipy,mtrbean/scipy,mingwpy/scipy,lhilt/scipy,mgaitan/scipy,mgaitan/scipy,perimosocordiae/scipy,vanpact/scipy,gef756/scipy,rmcgibbo/scipy,WarrenWeckesser/scipy,Dapid/scipy,giorgiop/scipy,behzadnouri/scipy,e-q/scipy,WillieMaddox/scipy,vhaasteren/scipy,trankmichael/scipy,petebachant/scipy,kalvdans/scipy,minhlongdo/scipy,mgaitan/scipy,mhogg/scipy,piyush0609/scipy,andim/scipy,maniteja123/scipy,pyramania/scipy,endolith/scipy,arokem/scipy,lukauskas/scipy,ortylp/scipy,mingwpy/scipy,nvoron23/scipy,zxsted/scipy,ndchorley/scipy,piyush0609/scipy,Stefan-Endres/scipy,anielsen001/scipy,piyush0609/scipy,haudren/scipy,petebachant/scipy,fernand/scipy,WillieMaddox/scipy,dominicelse/scipy,aman-iitj/scipy,grlee77/scipy,ndchorley/scipy,bkendzior/scipy,ChanderG/scipy,pschella/scipy,fernand/scipy,anntzer/scipy,pizzathief/scipy,Shaswat27/scipy,mingwpy/scipy,scipy/scipy,sargas/scipy,niknow/scipy,sauliusl/scipy,piyush0609/scipy,teoliphant/scipy,gertingold/scipy,jonycgn/scipy,ChanderG/scipy,surhudm/scipy,jjhelmus/scipy,niknow/scipy,maniteja123/scipy,mortada/scipy,pyramania/scipy,woodscn/scipy,ilayn/scipy,vhaasteren/scipy,njwilson23/scipy,kalvdans/scipy,newemailjdm/scipy,trankmichael/scipy,tylerjereddy/scipy,minhlongdo/scipy,sriki18/scipy,nvoron23/scipy,hainm/scipy,fredrikw/scipy,jsilter/scipy,nmayorov/scipy,e-q/scipy,lhilt/scipy,mtrbean/scipy,newemailjdm/scipy,mikebenfield/scipy,josephcslater/scipy,jakevdp/scipy,anielsen001/scipy,behzadnouri/scipy,njwilson23/scipy,lukauskas/scipy,gertingold/scipy,pyramania/scipy,gertingold/scipy,larsmans/scipy,aarchiba/scipy,gertingold/scipy,anielsen001/scipy,ogrisel/scipy,fernand/scipy,maciejkula/scipy,pnedunuri/scipy,zerothi/scipy,vberaudi/scipy,jsilter/scipy,woodscn/scipy,felipebetancur/scipy,larsmans/scipy,sonnyhu/scipy,sargas/scipy,pnedunuri/scipy,aeklant/scipy,ortylp/scipy,mingwpy/scipy,mdhaber/scipy,jsilter/scipy,efiring/scipy,mdhaber/scipy,ChanderG/scipy,gef756/scipy,sargas/scipy,FRidh/scipy,sargas/scipy,fredrikw/scipy,njwilson23/scipy,Kamp9/scipy,aman-iitj/scipy,jor-/scipy,FRidh/scipy,lhilt/scipy,behzadnouri/scipy,matthewalbani/scipy,jor-/scipy,vanpact/scipy,fernand/scipy,jseabold/scipy,aeklant/scipy,vigna/scipy,pschella/scipy,mtrbean/scipy,matthew-brett/scipy,befelix/scipy,piyush0609/scipy,e-q/scipy,perimosocordiae/scipy,kleskjr/scipy,mortonjt/scipy,nonhermitian/scipy,ilayn/scipy,aman-iitj/scipy,mtrbean/scipy,vberaudi/scipy,Stefan-Endres/scipy,anntzer/scipy,Stefan-Endres/scipy,jseabold/scipy,pnedunuri/scipy,argriffing/scipy,richardotis/scipy,chatcannon/scipy,Srisai85/scipy,Gillu13/scipy,endolith/scipy,apbard/scipy,minhlongdo/scipy,niknow/scipy,mgaitan/scipy,pyramania/scipy,vhaasteren/scipy,mdhaber/scipy,zerothi/scipy,lukauskas/scipy,sriki18/scipy,aarchiba/scipy,larsmans/scipy,argriffing/scipy,jjhelmus/scipy,Srisai85/scipy,matthew-brett/scipy,pizzathief/scipy,nmayorov/scipy,juliantaylor/scipy,WarrenWeckesser/scipy,giorgiop/scipy,vigna/scipy,FRidh/scipy,mortonjt/scipy,andim/scipy,gdooper/scipy,zaxliu/scipy,trankmichael/scipy,felipebetancur/scipy,pbrod/scipy,Eric89GXL/scipy,gertingold/scipy,Stefan-Endres/scipy,richardotis/scipy,piyush0609/scipy,gfyoung/scipy,newemailjdm/scipy,dominicelse/scipy,kleskjr/scipy,jakevdp/scipy,gdooper/scipy,dch312/scipy,andyfaff/scipy,jakevdp/scipy,tylerjereddy/scipy,Eric89GXL/scipy,rmcgibbo/scipy,sriki18/scipy,rmcgibbo/scipy,rmcgibbo/scipy,pbrod/scipy,tylerjereddy/scipy,andim/scipy,jjhelmus/scipy,felipebetancur/scipy,scipy/scipy,Shaswat27/scipy,richardotis/scipy,maciejkula/scipy,jakevdp/scipy,befelix/scipy,vigna/scipy,sonnyhu/scipy,ales-erjavec/scipy,FRidh/scipy,scipy/scipy,aarchiba/scipy,surhudm/scipy,gef756/scipy,Eric89GXL/scipy,lhilt/scipy,Kamp9/scipy,ales-erjavec/scipy,matthewalbani/scipy,jseabold/scipy,tylerjereddy/scipy,cpaulik/scipy,mikebenfield/scipy,fredrikw/scipy,person142/scipy,vberaudi/scipy,Gillu13/scipy,haudren/scipy,Eric89GXL/scipy,woodscn/scipy,gdooper/scipy,bkendzior/scipy,newemailjdm/scipy,njwilson23/scipy,felipebetancur/scipy,jamestwebber/scipy,kleskjr/scipy,andyfaff/scipy,Eric89GXL/scipy,jonycgn/scipy,Newman101/scipy,hainm/scipy,dch312/scipy,mortonjt/scipy,Srisai85/scipy,giorgiop/scipy,hainm/scipy,ortylp/scipy,pschella/scipy,mikebenfield/scipy,raoulbq/scipy,Dapid/scipy,fredrikw/scipy,apbard/scipy,efiring/scipy,josephcslater/scipy,Shaswat27/scipy,WillieMaddox/scipy,person142/scipy,apbard/scipy,sauliusl/scipy,ortylp/scipy,dominicelse/scipy,jamestwebber/scipy,nmayorov/scipy,befelix/scipy,mhogg/scipy,Stefan-Endres/scipy,aarchiba/scipy,vanpact/scipy,befelix/scipy,grlee77/scipy,mdhaber/scipy,befelix/scipy,cpaulik/scipy,argriffing/scipy,larsmans/scipy,giorgiop/scipy,rgommers/scipy,petebachant/scipy,teoliphant/scipy,jseabold/scipy,anntzer/scipy,bkendzior/scipy,arokem/scipy,Dapid/scipy,jamestwebber/scipy,zxsted/scipy,WarrenWeckesser/scipy,person142/scipy,jsilter/scipy,bkendzior/scipy,Dapid/scipy,anntzer/scipy,aman-iitj/scipy,mhogg/scipy,teoliphant/scipy,nvoron23/scipy,trankmichael/scipy,grlee77/scipy,newemailjdm/scipy,gef756/scipy,fredrikw/scipy,dominicelse/scipy,ilayn/scipy,mortonjt/scipy,andyfaff/scipy,andyfaff/scipy,pbrod/scipy,andyfaff/scipy,ilayn/scipy,perimosocordiae/scipy,jjhelmus/scipy,pnedunuri/scipy,mortada/scipy,minhlongdo/scipy,josephcslater/scipy,endolith/scipy,matthew-brett/scipy,endolith/scipy,fredrikw/scipy,cpaulik/scipy,argriffing/scipy,vigna/scipy,petebachant/scipy,richardotis/scipy,endolith/scipy,andim/scipy,lhilt/scipy,FRidh/scipy,kleskjr/scipy,gfyoung/scipy,behzadnouri/scipy,maciejkula/scipy,perimosocordiae/scipy,Dapid/scipy,njwilson23/scipy,jor-/scipy,person142/scipy,anielsen001/scipy,raoulbq/scipy,ogrisel/scipy,aeklant/scipy,aman-iitj/scipy,grlee77/scipy,newemailjdm/scipy,cpaulik/scipy,Kamp9/scipy,kalvdans/scipy,gfyoung/scipy,vanpact/scipy,jseabold/scipy,witcxc/scipy,Kamp9/scipy,woodscn/scipy,behzadnouri/scipy,mtrbean/scipy,perimosocordiae/scipy,Srisai85/scipy,gef756/scipy,perimosocordiae/scipy,jonycgn/scipy,matthew-brett/scipy,hainm/scipy,sonnyhu/scipy,WarrenWeckesser/scipy,futurulus/scipy